At this stage of the Inaugural Week game, nobody can be quite sure who is going to teach whom a thing or two about entertaining the power elite - Washington's Beautiful People or Atlanta's.

However it's done, though, it will be with gusto and exclusivity. Washingtionians such as the Averell Harrimans, the George Stevenses, the Henry Bradons and the Endicott Peabodys, to name but a few, predictably will entertain behind closed doors while Atlantans celebrate in less private surroundings.

"There's been a lot written about Carter barbarians swinging out of the kudzu," says Elkin Alston of Atlanta, laughing as loudly as a Southern aristocrat dares over the profusion of stories painting Georgians as somewhat less than civilized. "But we change our suits, too, you know. So we might as well put on black tie while we're at it."

That's what guests of Philip and Elkin Alston do in Atlanta where he is senior partner in the law firm of Alston. Miller and Gaines. And that is exactly what they will be doing here next week when the Alstons entertain supper guests before one of Jimmy Carter's six inaugural parties following his inauguration Thursday.

The Alstons are in a vanguard of socially prominent Georgians coming to town to whoop it up - graciously, of course - at intimate suppers, congressional receptions, brunches, luncheons and inaugural night balls.

To say nothing of the White House receptions Jimmy and Rosalynn Carter are giving the first two days they are in residence there.

Two Atlanta couples, the Edward Elsons (he's head of the Atlanta News Agency) and the J. Mack Robinsons (he's an investment banker) have joined forces to give a dinner Tuesday night at Florida House on Capitol Hill honoring Bert Lance, new director of the Office of Management and Budget and a former Atlanta banker, and his wife, LaBelle. Their guests will include Georgia's two U.S. senators, Herman Talmadge and Sam Nunn (plus Mrs. Nunn but minus Mrs. Talmadge), Georgia Gov. and Mrs. George Busbee, the James Roosevelts, the Elliot Janeways and Atlanta Newspapers chairman Ann Cox Chambers and her husband, Robert.

Mrs. Elson will wear an "old" Holly Harp design for the event and Mrs. Robinson is expected to wear a St. Laurent ("she owns quite a few," said Mrs. Elson. "Her husband was an early backer of St. Laurent when he started out in the couture business.")

Putting a party together long-distance wasn't the effort one might think, according to Susie Elson. The biggest problem was when the dinner invitations for Jan. 19 were mailed out and then later had to be changed.

Carter wanted the Cabinet to attend the Gala that night, so everybody was called and asked if they could come on the 18th. "They were so nice and said they were used to changes," Elson said.

Finding places to hold their parties has had out-of-towns scrambling for private clubs here.

Publicity about the marriage of former Carter lieutenant Greg Schneiders and his long-time roommate, whose reception followed at the staid old Sulgrave Club, kept one distant hostess-to-be on the edge of her chair. Like a number of non-Washingtonians, she had arranged to "borrow" the club through a friend here who belongs. After the Schneiders' affair, she feared the club might cancel such commitments.

The acceptance rate on Inaugural week parties has astounded some Washington hostesses. "Usually you figure on 60 per cent," says Ann Kinney who with her husband, Gilbert, expects a mix of foreign affairs experts and artists at their black-tie supper Thursday night before the big inaugural parties.

Art patrons and collectors themselves ("we have mostly abstracts"), the Kinneys originally intended "something small" for the five artists: Andy Warhol, Jamie Wyeth, Robert Rauschenberg, Roy Lichtenstein and Jacob Lawrence whose inaugural impressions will go into a limited (100) edition portifolio costing $2,500 and already sold out.

Of the lot, only Warhol appears to be a sure-fire no-show. He'll be in Teheran that day, relying upon his photographer to capture highlights of Carter's inauguration so he can do his Warholesque impressions later.

High on the list of those who will attend, however, are the Kinneys' "summer neighbors," Zbigniew Brzezinski, Carter's National Security Council chairman-designate, and Mrs. Brzezinski; Columbia University Professor Richard Gardner, whom Carter has selected to be in Ambassador to Italy, and Mrs. Gardner, New York gallery owner Leo Castelli; Corcoran Gallery curator Jane Livingston; chairman of the National Endowment for the Arts Nancy Hanks; Seattle Mayor Wes Uhiman, Georgetown neighbors like Yolande Fox, plus New York friends like fund-raiser extraordinaire Alice Mason.

Around the corner entertaining at a supper the same night will be the Democrats' elder statesman Averell and his wife, Pamela. Likely guests, among others, are Cheray and Peter Cuchin, who is coordinating all the music for the major Inaugural parties, they, like actress Lauren Bacall, are staying on as houseguests.

Giving other parties of their own around town will be George and Liz Stevens, entertainig for "Today's show host Tom Brokaw and his wife, Meredith, Frank and Jayne Ikard, hosting a fried chicken and grifts supper; Chub and Toni Peabody, for friends from the Peanut Brigade, and Muffy and Henry Brandon, entertaining "a few out-of-town guest for lunch one day - I'm really not terribly involved in it all."

Also not terribly involved, apparently, are John Warner and bride Liz Taylor. "They're doing absolutely nothing, not even the Gala," said a secretary. Warren, in fact, is speaking in Charlottesville the night of Jan. 20.

The week-long "People's Inaugural' gets under way unofficially tonight when Minnesotans and Cleveland Park neighbors of Vice President-elect and Mrs. Walter Mondale take over the Washington Hflton to fete them.

Sunday night, it's retiring Democratic National Committee Chairman Robert Strauss' turn to entertain by inviting reporters to the Pisces Club for an authenic chili feed.

On Monday night Strauss' successor, Kenneth Curtis, and his deputy at the DNC, key Carter campaign strategist Ben Brown, will join a smll, elite group at Chez Brown, where Presidential assistant-to-be Hamilton Jordan is also expected.

There will be fund-raisers (two, in fact, for civil rights worker John Lewis, a candidate for Andy Young's congressional seat); media parties; congressional and state society open houses, receptions, brunches, lunches, dinners and breakfasts - seemingly by the hundreds all week long. Some will even be admission-free.

Partly to help smooth the ruffled feathers of those excluded from many inaugural events, the D.C. Democratic Party is sponsoring a party at the Hyatt Regency the same night as the six inaugural parties. The attractions may be even more stellar. For the $25 charge, there will be Nancy Wilson, Van McCoy, Virginia Capers and Frank Hinton plus food. The bar will be cash.

Inaugural Parade route parties in offices overlooking the spectacle will probably be among the most coveted invitations for midday Jan. 20. Among the day's top hosts will be the National Archives' Dr. James M. Rhodes, who has invited 150; the law firm of Ginsburg, Feldman and Bress at 1700 Pennsylvania Ave., who have invited 200, and the Oliver T. Carr Co., at 1700, 1730 and 1747 Pennsylvania, who have invited 225.

(Nothing and no one will be left to chance, however. Secret Service spokesman Jack Warner said all buildings along the parade route - and the personnel involved - were checked out a few days ago.)

Southern hospitality won't be directed only at Washington's new arrivals. There's even a farewell planned.

That's a black-tie party (with hash bar) scheduled Tuesday night at The Class Reunion, a popular retreat of White House staffers for whom the event is planned.

Insisted one host with straight face and stiff upper lip: "It won't be an Inaugural bawl."