Twelve local condominium and cooperative apartment developers and converters have organized a trade group. An organizer said the group will work, in part, toward easing problems of renters in projects being converted to condominium ownership.

Guiseppe Cecchi, a founder of the new Condominium Developers Association, said the group is developing policies to assure apartments are converted. He cited the case of Parkfairfax, which his firm (International Developers Inc.) converted to condominium ownership in Northern Virginia in the early 1970s, as one where the problem was minimized.

"As I testified rfecently before a committee of the Virginia legislature, those 1,680 dwellings needed renovation," he said. "Our program for conversion to condominium ownership also provided leases to tenants who wanted to stay. No one was evicted. And 72 percent of the original tenants either purchased or leased dwellings."

James F. Roberts of Roberts-Magazine Corp. in Alexandria has been elected president of the CDA group. Members included Watergate Development Inc., Charles E. Smith Companies, Reston Land Corp., OTV Iinc., American Invsco, the Anden Group, Delta Development Corp., Development Resources Inc.,Erkiletian Construction Corp., Holladay Corp., Klingbeil Management Group Co., Virginia Landmark Association and Wintergreen Development Company.

The organization has set up its office in Cecchi's [d] suite on the 19th floor of the new Rosslyn Center building.

That office is also the temporary headquarters of the National Association of Condominium and Cooperative Housing, a new organization interested in condominium development and conversion nationwide. George Vavoulis, an executive with American Invsco in Chicago, is acting executive of that group.

"Local governments increase their tax yields two- or-three-fold on dwellings converted to condominium ownership," Cecchi said.