Chicago Public School Teachers' Pension & Retirement Fund, Illinois State Universities Retirement System, Champaign, and Illinois Municipal Retirement Fund, Oak Brook, could undertake a search for a general partner to oversee a joint private equity fund that would be managed by minority-owned managers. The three pension funds tentatively agreed to commit up to $25 million each. Michael J. Nehf, executive director of the $10.2 billion Chicago teachers' fund, said Mercer Investment Consulting would assist in the search. Mr. Nehf said it could take several months before a decision is made. Illinois SURS has $12.7 billion in assets; Illinois Municipal has $15 billion.