Male cats are the territory markers, not females. If she is peeing in the house (this is the more likely case than 'spraying') she may have a UTI...painful for her and she is just trying to relieve the pain and irritation. Or, she is under stress or a very dirty litter box will do it too. Possibly, she is older and beginning to have alzheimer type symptoms. I would give her a try with just short visits inside your home. Keep an eye on her and your other kitty(s). If she just can't adjust to your home, then make her a nice warm outdoor home.