A group of Montgomery County senators, drawing their battle lines with a flourish, vowed today "as a matter of principle" to block a portion of this year's $67 million local education aid package that would cost Montgomery, the state's wealthiest subdivision, $356,000 next year.

Even in a year when a large state surplus has erased traditional regional frictions in the General Assembly, the county's government and its senatorial delegation bridled at the notion that a piece of the aid is customarily recieves will be taken away.

Despite winning an unexpected victory by a narrow 7-to-6 margin in a Senate committee today, the senators are expected to have trouble keeping their promises. In Annapolis, the words "Montgomery County" tend to conjure up images of $200,000 homes and sweeping expanses of lawns and greenery -- images that hobble local legislators fighting for state aid.

"It's a Robin Hood hill," explained one of the Montgomery County lobbyists. "The only problem is that we're the sheriff of Nottingham."

The measure in question forces the county government to pick up 10 percent of the total payments made toward teachers' Social Security payments -- a cost that, for the last decade, has been totally financed by the state.

"This year they want us to take 10 percent, next year it'll be 20 percent, pretty soon they'll want us to pick up the whole thing," complained State Sen. Victor L. Crawford, who with his colleague, Laurence Levitan, is leading Montgomery County's troops.

The total cost to all local jurisdictions would be $6.3 million, a sum that would then be returned to the counties but not necessarily to the counties from whence it came. In returning the funds, the state would calculate each county's share by an "equalization formula" -- one which, in effect, takes funds from the rich subdivisions and gives it to poor ones.

The underlying fear of the Montgomery senators and of County Executive Charles W. Gilchrist is that the bill would set a precedent and lead to other measures in future years that also would use "equalization formulas" to cut down the country's share of state aid.

"It's a foot in the door," explained Gilchrist, who came to Annapolis in part to talk the situation over with House Speaker Benjamin L. Cardin, a Baltimore City delegate whose densely populated hometown stands to benefit most by the equaliation proposal.

"It's just the first bit of the wedge," added Crawford. Figures complied by the legislature's research division show that nearly half of the $19.7 million the county curently receives in state aid already is subject to "equalization formulas" that send far more money to poorer subdivisions.

"Someday, we'll be talking about 100 percent equalization," said Montgomery's lobbyist, Balir Lee IV. "We don't object when they take new state money and give more to the poorer areas. What we object to its taking part of our current payments and giving it to someone else."

Looking for allies in its legislative struggle, Montgomery has turned to another wealthy suburban area. Baltimore County, and to its neighbor, Prince George's, both of which also stand to lose some money as a result of the proposed redistribution.

Several observers felt the Montgomery senator's efforts were hopelessly quixotic, in part because the redistricbution of Social Security payments represents only a small portion of a massive aid package which, all told, means more aid for every locality, even Montgomery.

At least one Prince George's senator, Tommie Broadwater, already has voted against the Montgomery partisans in committee, and Baltimore County Sen. John J. Bishop Jr. said he would also refuse to join in their fight.

The united support of all three delegations from Montgomery, Prince George's and Baltimore County could kill the Social Security proposal in the Senate. A handful of defections, however, and Crawford's and Levitan's cause would be lost.

The furor also brought an amused reaction from some onlookers in the House of Delegates, who point out that the Social Security payments plan was introduced and supporterd by Lucille Maurer, an education expert who represents in Wheaton area of Montgomery in the House.

When asked about Maurer's role in the plan, the usually voluble Crawford gave a terse "No comment."