Do you have areas for them to "get away" from each other? Cat trees for example? How many cats do you have? If you only have two, can you separate them for a while, and then slowly reintroduce them? Have you noticed a pattern of what sets them off? How frequently does it happen? You also wrote about a cat being in heat on another thread - if your cats are not spayed/neutered, they can be more aggressive. Give more details, I'm sure someone will be able to help you out.