We don't have biting, but we do have the escalation of a minor dispute into a physical free for all between the almost 5 and 3 year olds. What I have been trying lately and am having success with is letting them own the problem. So instead of rushing in there and telling them who something belongs to and who had it first etc and solving it for them, I ask what is happening and they will tell me, then I will say something along the lines of "so that is the problem, what is your solution" and then they have to come up with a solution. If they are being stubborn I suggest something, like turns or an alternative item but more and more they are coming up with the solution on their own (with me standing by). It is music to my ears when they want the same thing and instead of grabbing and pulling at it (and each other!) I hear one of them asking if they can have the next turn with it with no help from me. Obviously it doesn't work all the time and you have to factor in tired/bad mood/stubbornness etc but we are making progress.

I think it is about giving them the tools to solve their own problems and then supporting them while they learn to put it into practice. It is hard though.