What is it that is making the cats want to hang out at your house? If you're not feeding them, it's kind of unusual that they would stick around. The PetSmart stores that have cats for adoption usually get them from SPCA or the Humane Society - the store doesn't actually get involved with taking in animals. The fact that your local animal shelter won't take them is ridiculous! This is a perfect example of why we have animal shelters to begin with! There are a bunch of online animal adoption groups and if you Google that for your area you may be able to come up with something. Good luck