Trustees of the $71 million Holyoke (Mass.) Retirement System yesterday picked Dreyfus Management as a small-cap equities manager and Fidelity Management as a real estate manager, said Helane Glidden, office manager. Each will manage $3 million initially. The money will come from reducing the system's allocation to Freedom Capital, which manages most of the system's assets in a balanced portfolio. The hirings followed recommendations of an asset allocation study conducted last year by Segal Advisors, the system's consultant.