Years ago I kept several male hissers as pets, and they all did just fine when housed together. Sure they would fight but they never really did any damage to each other. Plus without any females they really don't nave too much to fight over.
I keep a small group of males and females as pets. When the enclosure was too small (large KK) the males fought regularly, but after I upgraded them to a larger tank (5 gal) with more places to climb, the fighting has pretty much stopped. They hiss now and again, but that's about it.