You don't say what the sprayer's name is so I'm going to call her Princess, just for clarity. The reason she's spraying is she's feeling threatened by the other cats. Even if they are friendly toward her. Cats are solitary animals and it can be difficult to introduce others to the mix. 8 years ago I found a tiny 6 week old kitten that someone had abandoned. I took her home, even though I already had a 15 year male neutered cat. I kept the 2 cats separated for nearly a month and then introduced the kitten (Kalie) to my older cat (Snapper). There was a lot of hissing and some growling but I let them work it out, but kept close in case it got violent. They became best friends eventually and Snapper lived to be 18. We tried to get another cat after that but Kalie would have nothing to do with the new kitten. We tried everything but finally had to find a new home for the newbie. Some cats are that territorial and Princess may be one of them. Try separating the new cats in a back room if possible. Also give Princess tons of love and reassurance that she is your baby and you love her. Then try slowly to bring one of the new cats in, but be prepared that she may never be okay with this and you may have to make the same choice we did. Good luck Renee Renee