Are they neutered?

Are they outdoor/indoor cats? If they are allowed out, is there a possible queen(female) in your area?

This is either a dominance/ jealousy thing or a mating thing. Right now my youngest, Merlin is giving everyone socks, trying to find out who's the big cheese in our house.

Try this page, scroll down the page it actually deals with agression in cats! Hope this helps!...good luck! >^..^< ! http://www.catsinternational.org/articles.html