Senators get mail from constituents, from special interest groups, from the occasional loony. But only Sen. Rudy Boschwitz gets mail like this:

I have a marvelous grandson of 30 whom I would consider a very eligible bachelor in Washington. He is good looking, bright and witty. He is a gourmet cook and also makes great chopped liver. He is a graduate of Duke University and Yale Law School and is a practicing attorney in D.C. He has a wide circle of friends, mostly non-Jewish and especially the girls.

Dear Senator, you would make me so happy if some one on your staff would notify him personally when you have your next social function. In return I offer you my blessings, a finder's fee and a contribution to your next campaign.

Meet the Matchmaker of Capitol Hill.

So far this year, Boschwitz has sponsored five parties for Jewish singles who work on the Hill or around Washington. The parties usually correspond with a Jewish holiday, but if no timely festival exists, the senator finds another excuse. The next one, a Hanukah reception, is set for Dec. 12 at the Sheraton Grand.

Invitations go out to all offices on the Hill plus another 750 individuals on the mailing list. In July he threw a "Wine, Cheese and Looking Around" party, which admonished, "Better a shadchan yiddish for matchmaker than a shotgun." Prior to that, he invited Jewish singles to celebrate Lag B'Omer, a little-known religious holiday he describes as the only time during "a sad period in the Jewish year" when Jews are allowed to marry. If any marriages result from one of his parties, he says, the couple will receive a special prize.

He arranges dates for his sons, when they come to town, with eligible women on his staff -- an offer the staffers cannot refuse. Recently Boschwitz tried in the middle of a television interview to fix up his press secretary, Mary Lahr, with the male reporter.

His interest -- some might say meddling -- is, no doubt, not always appreciated. Yet a surprisingly large number of people seek out his matchmaking skills. He takes an interest in all affairs of the heart, but Jews are, so to speak, his specialty.

How does this fit in with his senatorial duties?

"This is my number one duty," he says.

But he doesn't just put relationships together. He also breaks them up.

"My Catholic scheduler was running around with a Jewish doctor. I and her parents disapproved, though she knew we loved her just as much. She eventually stopped running around with him," he says, satisfied.

Rep. Larry Smith (D-Fla.) has collaborated with Boschwitz since the second party. When Smith learned that the senator was looking for someone to cosponsor the get-togethers, he jumped right in. "I thought it was terrific. Any alternative to the usual singles thing is. It's a very viable and good alternative."

Smith has gotten his share of approval, along with pleas for help, from parents around the country. Ellen Lapidus, a legislative assistant for Smith, says she has received 20 to 30 phone calls since Hadassah Magazine published an article in October which mentioned the Boschwitz-Smith parties. "A woman from Dallas called to thank Smith for what he was doing. She said, 'I know I'm being a pushy Jewish mother, but my daughter works near the Hill and I'd like you to invite her to the parties ,' " recalls Lapidus.

Another Jewish mother wrote to Smith: "After reading my issue of "If you're supposed to get pleasure from doing nice things, then I am getting pleasure from this." -- Sen. Rudy Boschwitz Hadassah . . . describing your successful matchmaking . . . I am forwarding my son's name and address. He may not appreciate it or respond, but at least I've tried . . . He is 29, a vice president of his firm . . . owns his own house, and would like to share in life with an outdoor type of girl . . ."

Some of the parents don't want it known that they placed their children on the mailing list, fearing that if the children knew, they would never attend.

Nearly 200 people paid $10 each to attend last October's dinner celebrating the harvest festival of Sukkot, which would probably have startled and pleased their parents. Alise Orloff, 25, a Capitol tour guide, gives one explanation, "It's difficult to meet Jewish singles . . . I hope to marry someday soon and I want to marry within the faith." This was her second Boschwitz-Smith party. "They've been really nice. I really would like to keep going to them."

A Treasury Department employe identified only as Don, 27, agrees. "These parties offer a high grade of clientele. Not too many nerds, a lot of yuppies, cream-of-the-crop type of thing." He likes these parties because, he says, "It's not life or death for me. I go with a good attitude and that increases my chances of meeting someone."

At the Oct. 3 party, Boschwitz wolfed down a bagel spread thick with cream cheese, mopping up as he talked a glob of cheese from the linoleum with a napkin. Turning from the buffet table weighted with tuna, herring and whitefish salads, fruit and strudel, he noticed a couple talking nearby. "Did you know one another before this?" he asked. They both answered no. "See?" he said, obviously pleased. "Get their names."

Boschwitz began the parties last December because, he said, "I have four sons. They know of my emphasis and they know what my priorities are . . . Even though they are not here [in Washington], I think I still have an impact." None of his sons, aged 18 to 27, is married, and they do not date Jewish women exclusively, but, adds Boschwitz quickly in their defense, "They're doing all right."

Another reason he gives the parties, clearly, is because he enjoys it. "I think it's nifty. I really get a nice feeling from these people. And they seem to enjoy it," Boschwitz says. "If you're supposed to get pleasure from doing nice things, then I am getting pleasure from this."

Boschwitz says he has not encountered any negative response from other congressmen, nor from his staff. "Maybe some have thought it, but they haven't expressed it . . . People respect you when you are what you are."