Employees of the Coldwell Banker Commercial Group and several outside investors have signed a final agreement to purchase the Commercial Group from Sears, Roebuck and Co. The price was said to be in the $300 million range.

The present management and operating philosophy of the Commercial Group, based in Los Angeles and with local operations in Salt Lake City, will be continued, a spokesman said.Sears will continue to operate the Coldwell Banker Residential Group under that name. The Commercial Group has secured rights under the agreement to use the Coldwell Banker name for a transitional period of three years. During that time, the spokesman said, it will develop and adopt a new name and logo.

James J. Didion led employees in the purchase negotiations, while Frederic V. Malek and the Carlyle Group of Washington, D.C., led the outside investors. Malek will represent the outside group as co-chairman with Didion.

Investors in the new venture include the Carlyle Group, the Mellon Family Trust, Westinghouse Credit, Bankers Trust Co., a group of Japanese investors represented by the investment banking unit of Sumitomo Bank; and Malek, both individually and as part of the Carlyle Group.