Worcester (Mass.) Regional Contributory Retirement System is searching for a core real estate manager to run a $5 million portfolio. The $290 million system has not determined the source of funding. The search was initiated to maintain the systems real estate exposure, now at $11.5 million, as some of the older funds are winding down, said Kevin Leonard, the Segal Advisors consultant who is assisting. RFPs may be requested by e-mail from [email protected] The deadline for proposals is Aug. 29; system officials plan to make a selection by November.