Looking for a Book Where the Male Lead Joins the Police Academy's Famous Five

At one point, the hero is targeted by someone who wants everyone to stay away from him. The six of them pretend to split into two factions to draw that person out: the hero, Kenji, and Hiromitsu on one side, and the class representative, Jinpei, and Rei on the other. They even pretend to argue in front of their classmates.