Tenacity might be the only thing that Dr. Alan J. Ross and members of the Prolife Nonviolence Action Project have in common. Ross, a Bethesda gynecologist, and the antiabortion activists have been locked in a bitter contest of wills for six years.

The doctor's opponents want him to stop performing abortions. He refuses.

Armed with signs bearing slogans including, "Alan Ross Kills Children Here," antiabortion activists have picketed Ross' home in Potomac, his office in Bethesda and an abortion clinic where he works in Gaithersburg.

This long-running battle took an unusual turn late last month when Montgomery County Circuit Court Judge J. James McKenna signed an order forcing Ross to stop performing abortions at his Bethesda office because the picketers were disturbing other businesses at the Bethesda Plaza condominium at 8311 Wisconsin Ave.

The judge also found that Ross had violated an agreement that he would not perform abortions at the office.

The temporary order stems from a suit filed against Ross by the condominium association with the support of the protesters. A trial is scheduled for May.

The lawsuit against Ross is indicative of new strategies being used against abortion providers by their foes, according to abortion rights groups.

While most direct legal challenges to abortion have failed, an increasing number of abortion clinics are having their leases challenged by protesters who pressure landlords to evict abortion providers, said Richard Mintz, spokesman for the National Abortion Rights Action League.

Similar actions have been taken or threatened against clinics in Kensington, Allentown, Pa., and other places, according to abortion rights groups. Mintz added that the recent court ruling against Ross may be unprecedented. He also said bomb threats and violence against some clinics have driven insurance rates beyond affordability.

"I'd be very disturbed if {the protesters} are trying to kick {Ross} out because he is doing something controversial, not illegal," said Leslie Harris, an attorney with the American Civil Liberties Union.

Ross, 44, said the conflict has already landed the two factions in court a dozen times. The demonstrators have charged him with assault; he has charged them with trespassing. "I didn't know where the court was until these people came into my life," said Ross, who has been practicing in Montgomery County since 1978.

Ross said he plans to appeal the judge's order. "I'm not the person causing the trouble; the injunction should be against them {the protesters}. They are coming at me," Ross said.

While there are other doctors who perform abortions in Montgomery County, John Cavanaugh O'Keefe, the 37-year-old organizer of the protest group, said the decision to pursue Ross is "historical rather than logical."

The battle lines were drawn in the spring of 1982 when O'Keefe and his neighbors in Montgomery Village received fliers for the new Uptown Women's Clinic in Gaithersburg, which listed abortion as one of its services, O'Keefe said.

The protesters held sit-ins, which they called "rescue missions," at the clinic and occasionally at Ross' old office in Bethesda. During the last two years, they also have demonstrated outside the doctor's home.

"They sent fliers to the whole neigborhood, saying Dr. Ross is killing children," the doctor angrily recalled. Ross said he has tried to explain to his children, ages 6, 10 and 12, that while the protesters are disturbing, they "have a right to be there."

"It's very embarrassing to explain to guests what's going on out there, said Jeanette Cermak, Ross' neighbor. Cermak said she sympathizes with Ross: "I think the whole group is misguided."

The demonstrators have apparently pushed Ross into losing his temper more than once. According to Montgomery County court records, Ross was twice convicted of assaulting protesters in 1985, including an incident in which he jabbed a protester with a hypodermic needle. Ross maintains that the charges are "fictitious."

According to financial planner James J. McCarthy, president of Bethesda Plaza Condominium Inc., the picketers, who usually arrived on Tuesdays and Saturdays, "were mostly annoying." McCarthy said he spoke to O'Keefe several times about stopping the protests and was told, "If we got an injunction {against Ross, O'Keefe} would call an end to the picketing."

"This whole issue has been very traumatic for us," said Rick Sampson, who runs a counseling service for senior citizens down the hall from Ross' office. Sampson said some of his clients were upset, particularly when some of the picketers entered the office to distribute literature.

While O'Keefe claims to have nothing to do with the filing of the condominium association's suit, an announcement circulated by his organization in June stated: "Large-scale picketing will give more weight to their argument when a hearing is held in July, and the judge could tell Ross to stop performing abortions . . . . "

The condominium association also contended in its suit that Ross did not honor several promises not to perform abortions at that location. A May 1985 letter from Ross to a condominium representative stated: "I do not intend to run an abortion clinic in this office . . . . "

Last week Ross said, "I never made an agreement that I would never make a medically indicated, first-trimester abortion." Ross said that at his Bethesda office, he performed one or two abortions a week -- a level that, he argues, does not qualify his office to be an abortion clinic.

"Alan Ross has used this semantic dodge repeatedly," said O'Keefe. He said his group plans to resume demonstrations at the Gaithersburg abortion clinic soon.

Ross said he has not done any abortions in the Bethesda office since the court order, but said he refuses to give up his right to perform a legal medical procedure. "They are trying by any means to push me," he said. "I try to ignore them."