Cat freaked out by bully cat next door

DEAR JOAN: I have two cats and my neighbor has two. One of her cats is aggressive to only one of my cats.

Now my cat won’t come out of the room and she is peeing all over. I leave the balcony door open for them to go out. Are there any suggestions you can give me?

— Violet R., Mountain View

DEAR VIOLET: Cats can be highly territorial; male cats are more so, but females will fight to protect their territory. Cats, like humans, can also take a disliking to another cat for reasons known only to them.