When Mikki and Rosie go after it we separate them. I also make a loud noise as a distraction then get them apart. Tends to help to get them apart. My two will go after each other when they are jealous. Usually when DH comes home. They both are wanting his attention and a little scuffle will take place. However, when I intervene they know I mean business. Oh, and I guess it helps that I tell them daily that I am the alpha.
Lol.
As far as the "time outs". I agree with Ladyjane. Sometimes we all need a cool off moment. And if it is in separate areas that work than so be it. I can separate mine for just minutes and it gets my point across.