I don't know how they would interact with the porch kitties.

We had them at our old house; when you go out the back door to the porch, there is a set of stairs leading to the yard. We kept trash cans there with nothing in them but support poles for tomatoes. One day I went out and happened to peek down and there was a set of glowing eyes looking back at me! Found out later there was a whole family living in the can, momma and babies!