Hate to say it Hobbes, but they just need to get over it. They will fight and you will separate and get clawed in the process. But if you rescue the little one too much he might become (for lack of a better word) whimpy. I had a cat like that once. He became whimpy because I was always rescuing him from my other bigger cat. He became afraid of everything. You will have to, but try not to overdo it. Don't worry about it too much, they're just establishing order. They'll be best buds in no time (depending on their personalities ofcourse).