My cats interact. I did not ask them about the next cats that came to us- whether they approved or not. When I ran a medical practice, my way was to let the people under me hire their colleagues. It meant there was always compatibility. My cats? War! The Maine coon cats are large and intimidating to the new kittens. Tillie has an attitude. She walks around growling randomly, no questions asked. Everyone gives her wide berth. Peas is just a sweet kitten. She has been stomped on more than one occasion. She’s a victim. Nutley is her protector. Elle now is a secondary target. Interaction? It’s complicated. Everyone is on edge. I got a serious family feud around hereabouts.