MASSACHUSETTS Republicans are sharpening their cartographic pencils with relish as they draw up their version of new US congressional districts to conform to the latest population figures of the 1990 US Census.As in state legislatures around the country, Bay State lawmakers must take up the complicated decennial task of redistricting. But GOP officials here, who say they are fed up with Democratic lawmakers for delaying the process, are now trying to make things as simple as possible. Their idea is to eliminate as many incumbents as they can from the state's all-Democratic congressional delegation. "Meeting behind closed doors, privately discussing possibilities with the incumbent Democrats in Congress, the Democrat members of the Joint Committee on Redistricting are playing a cute game," says Leon Lombardi, chairman of the Massachusetts Republican State Committee. "They believe the later the start of the race, the more built-in advantages the incumbents have." In a bid to increase the political pressure on state Democratic lawmakers, Republican Party officials released last week their version of a new congressional redistricting plan that pits nine of the state's 11 incumbent Democrats against each other for the 1992 fall election. The plan would also open up four new district seats, including the city of Boston as its own district. Boston is currently represented by three separate US congressmen. GOP officials say their plan for Boston and other Massachusetts cities will allow minorities, which are concentrated in the city areas, to elect their own candidates of color. Members of the black community praise the Republicans' efforts to unite their neighborhoods in separate districts. "I think it is a step in the right direction in terms of minority empowerment," says Joyce Ferriabough, president of the Black Political Task Force. "I think that they are moving ahead with the process shows it can be done expediently." Gov. William Weld (R) has yet to propose his own redistricting plan, although he does favor the idea of making Boston one congressional district. "I think that they [the state GOP] should be commended for bringing this very important issue to the public attention. Time is really growing short," says John Moffitt, chief secretary to Governor Weld. Mr. Moffitt says Weld will file his own redistricting plan sometime next month. According to the Census, Massachusetts will lose one congressional seat and will be represented by 10 instead of 11 congressmen. The new GOP redistricting measure would pit Democratic US Reps. Jos Moakley, Brian Donnelly, and Joseph Kennedy II against one another for the 1992 fall congressional election. Some political observers say the GOP's strategy with the plan is to concentrate Republican suburban districts and reap benefits from a convenient alliance with the minority community, while undercutting urban Democratic incumbents. According to Steve Grossman, Bay State Democratic Party chairman, the people of Boston are happy with the congressional representation they already have. "Based on my conversations with many, many people of communities of color, ... overall they feel good about the representatives they have," he says, later adding: d rather three people representing Boston than one." But Mr. Lombardi says Boston has a large enough population to have its own congressional district. "The city of Boston in the old days - anything before the last census - was greater [in population size] than a single congressional district. It had to be split. It's a smaller community than one district now. What's the justification for splitting it three ways?" he says. GOP officials say their plan creates compact, contiguous districts and passes the one-person, one-vote test. They say the plan also fulfills provisions of the federal Voting Rights Act which preserves minority communities as voting blocs. The GOP historically has been the minority party here, and officials call their plan a beginning point for discussion. Both Democratic and Republican Party officials expect to see many more versions before one is finalized.