Naser Bytyci and Branko Smilic are dentists who pulled teeth from fighters on opposite sides of Kosovo's ethnic war. Five years into a tenuous peace between ethnic Albanians and Serbs, the dentists live in the same town and practice the same profession. But Bytyci, an ethnic Albanian, pulls only Albanian teeth, and Smilic, a Serb, pulls only the teeth of Serbs.

Bytyci says he would not mind fixing Serb teeth, but that all the Serbs in town refuse to visit him or Albanian doctors of any sort. Smilic professes to be uninterested in giving Albanians root canals.

"It is better for each side to take care of its own," said Smilic, a stout man with a round face. "Suppose a patient got angry and began blaming the doctor because he was Serb or Albanian?"

It is safer, too, he argues, because recent violence against Serbs demonstrated that the foreign peacekeeping troops here cannot protect the Serbs.

The divided dentistry represents a persistent problem for Kosovo half a decade after NATO-led forces pushed the Serb-dominated Yugoslav army from the province and freed the ethnic Albanians from rule by then-president and current war crimes defendant Slobodan Milosevic.

Not only are the majority Albanians and minority Serbs living in segregated, mutually hostile communities, but they have been unable to integrate even ostensibly neutral public services such as health care. The "parallel structures" mock the stated aims of U.N. overseers in Kosovo to create a multiethnic society in advance of talks designed to resolve the political status of the province, which remains officially part of Serbia.

Kosovo's problems have a cousin in Macedonia to the south. There, a seemingly innocuous plan to reduce the number of municipalities nationwide by consolidating several areas has riled the majority Slavic population, which identifies itself simply as Macedonian.

The Macedonians assert that the plan, part of a U.S.-supported program of ethnic reconciliation, will make worse what they call efforts by the Albanian minority to split the country in two. Albanians say they just want to redress gerrymandering that has kept them at a political disadvantage.

The Macedonians have called a referendum, scheduled for Sunday, to squelch the municipal boundary plan. Several Macedonian analysts speak darkly of renewed violence if the referendum fails. A riot by Macedonians in July -- with trash and cars burned and windows smashed in the town of Struga -- provided a taste of the possible consequences, they say. Conversely, Albanians predict violence if the referendum kills the plan.

All over the Balkans region, the violence that burned in the 1990s has been doused, but the basic conflicts are unresolved. General trends are often negative.

In Bosnia, efforts to bring Serbs, Croats and Muslims into a workable government partnership have stalled. Few refugees who were driven from their homes during Serb campaigns of ethnic cleansing have returned permanently. Nor have Serbs returned after fleeing such places as the Bosnian capital Sarajevo at war's end. Croats remain segregated from Muslims in the western city of Mostar, touted as a symbol of peace when its graceful Ottoman-era bridge was recently restored. The town is almost totally devoid of Serbs.

Further afield, ethnic rivalry within Serbia and Montenegro, the last remaining chunks of Yugoslavia still glued together, threatens the country's unity. In 2006, the two republics are scheduled to vote on whether to remain united. Some Montenegrins are campaigning for secession.

Officials of the European Union, which has pressed to keep Serbia and Montenegro in one piece, say they fear that a Montenegrin exit would create an epidemic of breakups in neighboring countries: Serbs and Croats would want to go their own way in Bosnia, as would Albanians in Kosovo, other parts of Serbia and Macedonia .

A visit to Kosovo produces a sense of movement away from conciliation. The province held parliamentary elections on Oct. 23, but all but a handful of the approximately 120,000 Serbs who live among 1.7 million Albanians boycotted the vote, even though Serbs are guaranteed 10 of the 120 seats in the legislature.

In March, Albanians rioted, burning thousands of Serbs out of their homes. Nine Serbs and 12 Albanians died in the violence. Many Serbs left in the aftermath, resulting in a net loss of the Serb population for this year, U.N. officials say.

Smilic sent his wife and two children into exile in Serbia to escape the house burnings. He said he remained behind in part for protest, in part for economic advantage. The Serbian government in Belgrade pays him a stipend to stay put. He also collects pay for his dental services from the Albanian government in Pristina. However, he resists demands that he integrate with the Albanian staff at the main health center in the town.

He said that after the 1999 war, the center was renovated and the Serb staff, reduced from its prewar dominance, asked for a separate entrance for both medical personnel and patients. When that was refused, the Serbs set up a clinic in a private house.

"Of course, I don't think our Albanian colleagues would attack us if we went to the health center," said Smilic . "But there is danger from outsiders." He says the root of the problem lies in Albanian demands for full independence from Serbia, a subject that will arise at international talks proposed for as early as next year. "They want to be independent, and that means no Serbs. We can't move freely around here now, you can imagine if the peacekeepers leave and just the Albanians are in charge," he said.

Bytyci says the Serb fears, while authentic, serve as an excuse for radicals in that community to avoid any contact with Albanians in any institution. "We have three entrances to the health center. The Serbs can use any one they want," he said at his dental office near the clinic. Serb doctors and dentists "are taking money from the Kosovo government, but refuse to coordinate. No one knows where and if they work. They just come once in a while, take a share of medicines and disappear."

Bytyci said he has complained about this to UNMIK, the U.N. administrators in Kosovo. He said the Serbs receive almost a quarter of the local health budget, which, according to Bytyci, is excessive given their proportion of the town population. "The U.N. says it has to be careful. They don't want to upset anyone, so they don't do anything," Bytyci said.

U.N. officials acknowledge the problem but are reluctant to take dramatic steps. "At this stage, a lot of progress does not depend on the international side. You need a lot more from the local communities," said Peggy Hicks, director of UNMIK's office of returning refugees. "That's the key ingredient."

In Macedonia, unlike Kosovo, Albanians and Macedonians work together in government and have not adopted strict separation. Macedonians outnumber Albanians by about two to one in a total population of more than 2 million.

The proposed municipal reform originated in the so-called Ohrid agreement, which was negotiated under U.S. and European Union mediation in 2001 in a city by that name to end a seven-month armed revolt by Albanians. Albanians in Kosovo abetted the fighting.

Under the Ohrid deal, the Macedonians and Albanians agreed to increase the use of the Albanian language in government offices and to increase Albanian employment there. In recent weeks, envoys from the United States and E.U. have paraded through Macedonia to campaign against overturning the municipal reorganization plan. The E.U. has warned Macedonia that the dust-up could delay Macedonia's eventual membership in the union. Marc Grossman, the U.S. undersecretary of state for political affairs, advised that "Macedonia again faces a choice between the past and future," the Reuter news service reported.

In Struga, the plan yokes outlying villages and city under a single administration and makes Albanians the majority in the new political unit. At first, the Struga riot was directed against the local political offices of Macedonia's defense minister, Vlado Muchkovski, who was visiting the town, but it spread to other parts of town. Attitudes have not softened since.

On the Corso, the main pedestrian promenade in the resort town, cafe owners Micko Markovsky, a Macedonian, and Nusrat Ziba, an Albanian, serve about the same quality cappuccino and play the same Euro-pop music over their boom boxes, but agree on almost nothing else.

"We have change after change and they favor the Albanians," said Markovsky, who owns the Mia Pizzeria and Bistro. "What we need is jobs and the government concentrates on things that are not needed instead. This plan looks like a road to breaking Macedonia into two."

Ziba, owner of Queen's Bar, claimed that police stood aside as rioters rampaged up his street. "The Macedonians are used to privilege and don't want to recognize us as equals," he said. "Believe me, if we rioted like they did, there would have been plenty of dead Albanians around."

A Kosovo Albanian mother holds her son's picture during protest in Pristina to call on authorities to resolve fate of thousands of missing Albanians.