Guided by an $18,000 poll of D.C. voters, a number of black business people long allied with the Barry administration are now shifting their support to Democratic mayoral candidate John Ray, according to leaders of the group.

Some members of the group, which includes prominent and politically well-connected entrepreneurs, city contractors and bankers, are holding a major luncheon for Ray today, setting the stage for a timely boost in his campaign contributions less than five weeks before the Democratic mayoral primary.

In an interview yesterday, Ray said the group's backing also will help him blunt recent criticism by rival Walter E. Fauntroy that Ray was overly dependent on support from suburban developers.

Ray said the process that led to the group's endorsement -- a poll last month of 721 likely Democratic voters and a round of private interviews with the major mayoral candidates -- signifies the political maturation of Washington's minority business community.

"These people went about this endorsement in a very sophisticated way," said Ray, an at-large D.C. Council member. "Given the recent tone of the campaign, this is significant because it puts the lie to that tone."

Sources familiar with the group's deliberations, poll and candidate interviews said the loose association of business leaders was guided in part by Roy Littlejohn, who has held several major D.C. contracts, and William B. Fitzgerald, president of Independence Federal Savings Bank.

In addition to Littlejohn and Fitzgerald, neither of whom could be reached for comment, the group endorsing Ray today includes Arthur M. Reynolds, the city's bond counsel who is the law partner of Barry defense attorney R. Kenneth Mundy; former city administrator Elijah B. Rogers; local businessman R. Donahue Peebles; Pedro Alfonso, president of the D.C. Chamber of Commerce; and Versharn Scales, a construction contractor.

In the wake of Barry's June 13 announcement that he would not seek a fourth term, key figures in the group sought to coalesce behind a single candidate in the Sept. 11 primary, according to sources.

Ronald L. Lester, whose business partner, Diane T. Feldman, had been Barry's political pollster, was commissioned to survey likely Democratic voters to determine who among the primary election candidates was most popular.

Lester's poll, conducted July 5-11, showed Ray with a commanding, but not necessarily insurmountable lead, followed by candidates Charlene Drew Jarvis, Fauntroy, David A. Clarke and Sharon Pratt Dixon, according to sources.

Ray performed well among black and white voters alike, although some of his support was soft, while Jarvis had gained some momentum over the summer, the Lester poll showed.

Lester reported his poll findings in a July 12 briefing to 25 minority business leaders and political operatives at a downtown hotel.

Those attending the briefing included many of those endorsing Ray today, as well as Delano E. Lewis, the president of C&P Telephone; Ivanhoe Donaldson, a former deputy mayor; attorney David Wilmot, who is chairman of Eleanor Holmes Norton's campaign for D.C. delegate; and business executives Carroll B. Harvey and Ruby B. McZier, two strong supporters of Fauntroy's candidacy.

Robert L. Johnson, Fauntroy's campaign manager, also played a significant role in bringing the business people together, sources said.

Harvey, the owner of a major road paving company, said yesterday that Lester's poll indicated "extraordinarily soft" support among voters for all of the Democratic primary candidates. Although Ray was leading, "the support for John is soft and can be turned," Harvey said.

Armed with the poll results, the black business leaders interviewed several of the Democrats, sometimes twice. Ray, for example, said he was interviewed once in Fitzgerald's office and again in Littlejohn's office.

Ray said Fitzgerald peppered him with questions about Ray's commitment to minority business, particularly those that have prospered under the Barry administration's aggressive program of developing and contracting out to black-owned enterprises.

Minority contracting practices have stirred controversy during the nearly 12 years of the Barry administration.

While Barry has been praised by his supporters for imposing requirements that city contracts include minority-owned businesses, his minority contracting program also has been the subject of lengthy investigations by the U.S. Attorney.

Fitzgerald took issue with a statement Ray made earlier in the campaign about "sweeping out corruption and cronyism" and suggested that "I shouldn't be putting everybody in the same category," Ray said yesterday.

Ray, noting that his political rivals may criticize his garnering support from longtime Barry supporters, said he let Fitzgerald "know where I stood, which is whether you're Mr. X, Mr. Y or Mr. Z, everyone's going to have to comply with the regulations.

"I will promote good quality work" by minority contractors, Ray added. "And where there's corruption and cronyism, it will be swept out."

Jarvis sharply criticized the group's action, describing the participants as a "small group of business owners who want to be in control of the benefits of government." She said she had an opportunity to win their endorsement, but she "resisted their control."