Cambridge (Mass.) Regional Retirement Board is searching for a private real estate manager to run $20 million. Officials at the $534 million plan will consider firms using core or value-added strategies and open-ended or closed-end funds. The search was prompted by the system's doubling its real estate exposure to 10% of assets. Funding will come from cash. A selection might be made by the end of the year, said Ann C. LeDuc, executive director. Segal Advisors is assisting.