Cat stays outside all the time because of other cat, help?

get lots of toys and confine them one at a time to a single room for part of the day to give sasha a break i had an old cat and a young cat in a very similar situation. if they each get to go in the "play room" it will be fair to both. and keep the door to that room shut so it is special for them to go into that room you want them to like it not to be a punishment.