I have 7 cats, all indoor. Whenever I introduced a new cat into the household, the others would get upset, hiss, check out the new intruder in their territory. I have two that are declawed (came t hat way) and the others are not declawed. It always took up to a week for the new one to feel comfortable, but right now, I have certain cats that will cuddle up with each other, but o nly certain ones, and the rest just go to other cats. they seem to have their own hierarchy and there is a dominant cat in the house, and I think it is becuase he is the largest and the other cats know it. Eventually, I believe all your cats will get along, but it will take time. Good luck.