Are my bunnies fighting?

When I had been in school for about a month since summer I got a bunny and my sister got a bunny. They are both girls. Lizzy is a small black and white lion head she bites but not through clothes and never wants to be caught. Pomme is a fat lopped eared bunny who likes to nibble on clothing and bob her head up and down. She is easily caught but kicks her feet once shes caught. Now when we got these bunnies the breeder had them in a cage with 4 other female bunnies. Lizzy and pomme just happened to be snuggling up agianst each other in the corner of the cage. We were sure they liked each other. At first they seemed to. We keep them both in a 6ft by 3ft by 2f cage outside. When ever we bring them inside to play pomme is put on the couch and lizzy on the floor. Lizzy usably jumps up on the couch with pomme. When we have a carrot or apple they each fight over it... Lizzy occasionally nips pomme. at first we though she was grooming her. but than not to long ago we discovered a lot of pomme's all over the cage. Are they fighting? I thought they loved each other and were buddies. Is it a thing over who is the dominate bunny?