When Montgomery County's state senators gathered recently for a private dinner in Bethesda, they had in their midst one guest who personified for them the major pitfalls of the upcoming session of the Maryland General Assembly.

Baltimore Mayor William Donald Schaefer was at his cordial best, presenting the suburban legislators with a holiday "wish list" of more than a dozen state spending proposals, including millions of dollars for city schools, police, harbor dredging and aid for the homeless of Baltimore.

"It was all very polite, but what he was really saying was that it's a bottomless pit," said state Sen. Sidney Kramer (D-Silver Spring), the delegation chairman. "If you strip away the veneer of the city's proposals . . . it means that Montgomery County will be bearing the major load of financing those projects."

Today, less than a week before the legislature opens in Annapolis, lawmakers from the most affluent jurisdiction in the state find themselves in an unusual bind. They are determined to make 1985 the year that Montgomery sheds its image as the state's "golden ghetto" -- a wealthy county that poor-mouths such political rivals as Baltimore -- while simultaneously fighting for increased state assistance to help the county cope with its phenomenal growth and demands for roads and schools.

In past sessions, "Montgomery County very often got into a defensive posture, beating back proposals going to other parts of the state," said Del. Gene W. Counihan, a Democrat who lives in the booming "upcounty" area around Gaithersburg. "This session requires an offensive strategy. It's appropriate, because of our unique problems with growth and traffic."

Many Montgomery delegates and senators are still buoyed by what they say was their single most important accomplishment of 1984: fashioning an alliance with fellow suburbanites in Prince George's, Howard and Baltimore counties to wring a $3 million Ride-On bus subsidy from an often hostile legislature.

But some fear privately that Montgomery may be unable to re-create that unity this year, given the fractious politics of a House and Senate whose members are jockeying for the 1986 elections.

State Sen. Howard A. Denis, a Bethesda Republican, said only half-jokingly, "I'd like to see a filibuster starting on day one and ending on day 90." Legislators "will see less consensus and more fractured leadership," especially in the House led by Speaker -- and gubernatorial candidate -- Benjamin L. Cardin (D-Baltimore), Denis added.

There are other problems, as well, lawmakers said.

The county's new legislative lobbyist, Thomas B. Stone Jr., is untested in Annapolis and must hone the negotiating skills that he learned as a top aide to County Executive Charles W. Gilchrist, legislators pointed out.

On the Senate side, observers say Kramer's delegation may be torn by the political aspirations of Sens. Larry Levitan and Stewart Bainum Jr., two Democrats mentioned as possible running mates to Schaefer if the mayor runs for governor.

"The '86 elections could color the work of the legislature," said Del. Ida G. Ruben (D-Silver Spring), the House delegation chairwoman who is marking her tenth year in that chamber. "It means we may have to work harder not to be taken to the cleaners, and a lot of that depends on how progressive the city is."

In the county lexicon, the "city" is not Rockville or Gaithersburg, but Baltimore, the perennial object of Montgomery's envy (for its effective lobbying staff and projected $7.5 million in state density aid this year) and scorn (for Schaefer's unflagging efforts to win more money for his city, often at the expense of the suburbs).

Montgomery's legislative leaders are threatening to fight any major funding proposal for dredging Baltimore's harbor, a project that is expected to cost at least $150 million in state and federal money. They say that such a proposal would disrupt funding for public works projects elsewhere in Maryland.

Montgomery probably will relent on Baltimore's request for $10 million in additional police funding and "density" aid based on the city's population, officials said.

The local delegations expect to win $1.2 million in aid to Montgomery College, part of a $9.3 million package to help all community colleges in Maryland. Montgomery's senators and delegates also predict relatively easy passage of major bond proposals to assist two local hospitals and the city of Gaithersburg.

The bond proposals are indicative of Montgomery's new-found willingness to press hard for special project funding, several legislators said.

"In the past, we've been disorganized in selling our position on issues such as bonding," said Kramer. "Because we haven't attempted negotiation, what bonding bills passed did so out of happenstance."

The county is proposing bond programs that would give $750,000 each to Suburban Hospital to upgrade its emergency care services and Holy Cross Hospital for hospice care, Kramer said. Montgomery also is seeking state funds to upgrade a commuter rail station in Gaithersburg and other projects in that city.

The political struggle over bonds and other issues "means a session of many small brush fires," Kramer said. "Our success is going to depend on coalitions with other counties -- which can work, as we proved last year. This year we need a repeat performance."