hitting / sharing

How do you with more than 1 lo deal with sharing and toys? It seems like things between ryder and akaia just keep getting worse and worse... Ryder has started hitting akaia (which is more of a shove not that that is any better) along with a no akaia mine! Akaia has been taking things more from him too, which I'm working on, but she now finds it fun to hit him with toys which I can only imagine is fun because she sees ryder hit her. I've been working on teaching ryder to move and take a minute when he is so mad with her that he wants to hit her. DH has been home and watching them while I do stuff in other rooms and last night put ryder in a timeout for 10 minutes and took a toy away. Today I heard what sounded like a spank, but actually sat down and talked to him. He says he learned hitting from me, and I'm at a loss. He doesn't do it at preschool at all it is only to akaia and occasionally to us if he is really mad. Any suggestions?