Melrose (Mass.) Contributory Retirement System, with $43 million in assets, is searching for a style rotation investment manager that will overweight domestic growth or value stocks, depending on what is in favor. The portfolio will be $6 million. Proposals are due May 5. The fund has been contemplating such a hire for some time, said Kevin Leonard, the Segal Advisors consultant who is assisting. Money for the new mandate will come from Fleet, which manages the bulk of the pension funds assets in a balanced portfolio.