Fighting for Batman

I currently have a fight going on in my daughters bedroom. She and her friend are fighting over Batman. They both say that their Barbie is his girlfriend. I have to go intervene, each girl gets the doll for 5 minutes. Seems fair to me, then Sarah starts to cry bc her girlfriend has told Batman that it doesn't matter what Sarah says because he knows his heart belongs to her Barbie doll.  I swear these children crack me up.