Officials at the $1.1 billion Houston Police Retirement System expect to hire by the end of April a large-cap value manager, a growth manager and an opportunistic equity manager, said John E. Lawson, executive director. Responses to RFPs are being reviewed now, he said. The three firms will replace one or more core equity managers the board will identify later. The board also will decide how much each new manager will be allocated. RogersCasey is assisting.