Oh, you mean putting two males in? yeah, that can help. But keep an eye on things for the first hour or so if you do that--my males have all been roommates in the past, and don't act up towards one another. But I've heard unfamiliar males will often posture aggressively when there's a female at stake.

But I've also heard that getting them to feel like another male is moving in can trigger breeding in reluctant males.