The Wirthlin Group, a McLean-based research company with 300 employees, has acquired Welch Communications Inc., a five-employee Arlington advertising and consulting firm that specializes in direct mail. The acquisition price was not disclosed.

David R. Welch, founder and president of Welch, has been named senior vice president of the Wirthlin Group. The Welch employees will remain at their office in Arlington and will be known as Welch Communications, a division of the Wirthlin Group.

Hay Systems Inc. of Washington will evaluate current and projected manpower and training for the Air Force at its personnel headquarters at the Pentagon under a contract worth a potential $23 million over five years.

The contract includes systems engineering, analysis and evaluation at the Pentagon and at various locations nationwide.

Jaffe Associates Inc., a Washington public relations and marketing firm, has agreed to an affiliation with The Lexica Practice Consultancy, a British firm, to market professional services in the United States and Europe.

The agreement allows services to be exchanged between each company's sales agents and customers in their respective countries.

"A lot of our American clients are very interested in taking products and services to Europe," said Jay M. Jaffe, president. "You have to have inside information from over there to know how to develop and market products."

RCG/Hagler, Bailly Inc., a Washington consulting firm, has won a $1.5 million contract from the World Bank to help Indonesia with an energy conservation program.

RCG/Hagler, Bailly is the sole contractor for the two-year industrial project, which was the result of an international competition with six other firms, said John C. Franke, manager of business development for the firm.

The company will help Indonesia plan, promote, coordinate, implement and monitor its conservation activities.

American Systems Corp. of Chantilly has acquired the assets of Bycom Corp. of Atlanta for an undisclosed amount.

"With the addition of Bycom, American Systems is better able to serve our customers in the telecommunications industry," said F.G. Ramsey Jr., president of American Systems. Ramsey said the acquisition will give ASC the ability to provide total installation services.

Bycom will continue to operate under its name and will be a division of American Systems.

Baltimore Gas And Electric Co. will purchase a portion of its power from Pennsylvania Power & Light Co. for 11 years beginning in 1990. The purchase will allow BG&E to maintain reserves during the next 10 years and also will provide flexibility in scheduling power plant additions in the late 1990s, BG&E spokesman Charles Franklin said.

The agreement allows BG&E to buy 125,000 kilowatts of electricity from PP&L's Susquehanna Steam Electric Station in Berwick, Pa., at favorable rates compared to other options. BG&E will not acquire any ownership interest in any of the units, however.

Stock in Baltimore Bancorp, whose subsidiaries are the Bank of Baltimore and Municipal Savings Bank FSB, is being traded on the New York Stock Exchange. It previously had traded in the Nasdaq over-the-counter market.

According to the company, this is the first time a bank based in Maryland or Washington has been approved for listing on the exchange.

Baltimore Bancorp has 49 banking offices and two savings and loans in the area.

Top executives of Hofheimer's Inc., a Norfolk-based shoe retail chain, have bought the firm from a British holding company for $29 million.

Anthony V. Beechey, Hofheimer's chief executive officer, announced the management buyout from Ward White Group PLC.

Three senior managers -- Aubrey Layne, Howard Kramer, and Maurice Benton -- will be minority shareholders, according to Beechey.

The four paid 55 percent of the purchase price, with Sovran Financial Corp. providing the balance. Beechey said none of the chain's 88 stores would be closed and there would be no layoffs.

Ward White purchased the Norfolk-based shoe chain from the Hofheimer family for $23.5 million in 1982. Last year, the company did $55 million in business.

Announcements of news and developments affecting Washington area companies should be sent to Pamela Babcock, Researcher, Business News Department, The Washington Post, 1150 15th St. NW, Washington, D.C. 20071. Information must be received the Monday before publication to be considered for inclusion in Washington Business.