Alan Iezman is leaving his post as senior talent agent with the William Morris Agency to become a partner in the indie production company of Jack Grossbart and Joan Barnett, which will now be known as Grossbart/Barnett/Iezman Entertainment.Iezman will head a newly formed management wing at the company, which has produced such telefilms as “The Preppie Murder” and “Something to Live For: The Alison Gertz Story.” William Morris represents Grossbart/Barnett Prods. (the company’s former name) and will continue to handle the new entity. Iezman, confirming the move, noted that he’s spent more than 17 years at WMA and that the new arrangement was “the best of all possible worlds,” allowing him to work in talent management and eventually open up the door to producing telefilms and features. Grossbart added that the management arm would allow the partners to have a more active role in packaging talent for their own productions and “become a multifaceted company”–emulating entities such as Brillstein-Grey Prods. and Moress Nanas Golden Entertainment, which dabble in management as well as production. “It’s kind of a changing time in our industry,” Barnett said. “This made sense as another business for us to get into.” The arrangement reunites Iezman with Grossbart, who had been his mentor at WMA before latter left the agency in the early 1980s. Iezman, who started in WMA’s mailroom, oversaw the agency’s TV and then the motion picture talent divisions. Grossbart/Barnett Prods. is currently producing “The Woman Who Loved Elvis,” an ABC movie starring Roseanne and Tom Arnold, and has projects in development at CBS and HBO. The company entered into a three-year agreement in February 1992 to develop and produce telefilms and miniseries in conjunction with HBO Worldwide Pictures.