I have a mean girl cat
I had three female Ragdoll cats, all living together peacefully, but one really is the Alpha female, Cali. June of last year I rescued a pregnant stray, two weeks later she gave birth, 8 weeks later they all got spayed and got adopted but we kept Amy, the mom cat.
During her pregnancy and while the kittens were here Amy was very protective of her surroundings. We kept her in a closed off unused guest room where she had everything she needed for her and her babies. If one of the other cats so much as looked in she would go after them, mama cat style. The minute the last kitten was gone she was excited to roam the house and didn't mind the other cats, but Cali would chase after her. Amy is the sweetest cat, she gets along fine with the other two girls and she has no problem when Cali approaches but Cali growls and chases her off. Cali is on a mission to make Amy's life hell, she watches Amy with every step she takes.
Now she is preventing Amy from using the litterbox, which is in the laundry room. Amy is using the kitchen floor in a corner she always goes to to poop.
We have tried everything we can think of to make Cali less jealous, but she is just a mean girl when it comes to Amy. What can we do to help Cali chill out? It isn't Amy at all, she ignores Cali until Cali messes with her, but I can't have Cali doing this to Amy. It has been over a year, we thought Cali would calm down but she hasn't.