Intergrating

Question
Hi, we have two indoor cats that are both neutered males. They grew up together since they were kittens. We also have an outdoor cat that has been around since he was a kitten, and we pick him up and pet him, he acts just like a pet. He is also a male (not neutered) We would like to integrate these guys together. We let the two indoor one's outside to meet the outdoor one, and one of them doesn't seem to be bothered, but the younger one (he thinks he's a baby) doesn't like the outdoor cat at all. He hisses at him, but has never gone after him. Any idea's on the best way to integrate these guys without the indoor cat's feeling invaded or threatened? The outdoor cat can't be more then 1 year old and the indoor one's are 3 or 4. They play with each other through the window's all the time and act interested in one another. The outdoor one doesn't mind the indoor cats at all, he wouldn't be the problem. Hope this is enough info, thanks for your help!

Answer
HI Jill,

How wonderful of you to bring the stray kitty indoors for a safe loving life. Your cat who hisses at the outdoor cat probably feels a little threatened and is defending his territory. However since he hasn't been aggressive beyond that  it's a good sign. I have written an article on how to introduce a new cat to resident pets, if you follow these steps you will have the best chance of household harmony!

http://catnet.stanford.edu/articles/introducing_cats.html

Good luck :)