Kids fight about things, Charlie. It's one of the ways they learn how to deal with and resolve conflicts. And taking away the object that is being fought over teaches kids nothing. Even worse, it makes it more likely that they will find something else to fight about. They have to learn how to resolve their own conflicts at some point, without you interfering with their lives.
If the fighting is physical, then you have reason to intervene. But if it's just your typical kid's shouting match, then leave the situation alone and let them work it out. I fought with my siblings all the time as a kid. But I turned out okay, and so did they. We're all close now. That's what will happen to your kids. Today's quarrels are tomorrow's friendships and love.