@CatsBirdsFishRULE,
I don't know what makes you think they're related, they're both mammals but you'd have to go way back to find a common ancestor.
Cats are carnivores and hunters, they will have a go at the rabbits given half a chance. A lot of it depends on the individual rabbits and cats. When I got my first rabbit we already had a cat. As soon as he got the opportunity that cat went for the rabbit. Unfortunately for the cat, it was a very big rabbit that could handle itself, and the cat ran off with its tail between its legs. After that, the cat left all rabbits well alone, regardless of size.
So unless your cats have all been given a good kicking by feral rabbits, you need to take care to protect the rabbits.