Colorado Public Employees' Retirement Association, Denver, is interviewing finalists in its search for a manager to run a Lehman Aggregate index account, said Katie Kaufmanis, spokeswoman for the $29.4 billion fund. Officials hope to choose a candidate by the end of July; Ms. Kaufmanis declined to identify the contenders. It will be a new allocation, and the amount has not been determined. Funding will come from cash. The system's current fixed-income target is 25% of total assets, and it currently has 20% of assets in active fixed income.