Some cats want to control things. How can we tell these cats to stop bossing the other cats around?
We have to figure out what the cat is asking the other cats for. Because whether it's a kitten asking an older cat to play, a stubborn cat seeing if another cat will give up a favorite windowsill, or a hungry cat trying to eat everyone's food, knowing what the cat wants is going to guide our next step.
We must recognize that we can't ask the cat not to play, sit on the windowsill, or eat. We have to show them there is a different way to get what they want.
When we see the cat bothering the other cats, we give them what they want. Call them over with a toy, make a fuss over the food to draw them over, or move them to a free windowsill.
By getting the cat to notice that we are proving what they want, we will teach them they should ask us when they aren't getting what they want from the other cats.
We can call their name to get their attention, or, if we have to, squirt them with a spray bottle with plain water when they make the other cats annoyed. Put them in a time out in an empty room, away from the cat they are annoying.
ALWAYS follow up ten minutes later, to let the cat our of the room or say nice things to them to show them that they are still our friend.
Soon, they will realize bad things only happen when they bother the other cats, and good things come from bothering us.
For more about cats and their group behavior, see my articles on Cat Conflict.