I realize you want to avoid as much bloodshed as possible during the integration process, but its just not 100% possible. Resign yourself to the fact that there will be bad language (probably both yours AND the cats'), there will be fur lost and they will fight. Of course, try to minimize this. I've had luck with letting them get to know each other on opposite sides of a sturdy baby gate. Or maybe just under the door. Don't play favorites, give both sides the chance to be the "home team". And you'll probably have to deal with territorial spraying/peeing. I gave up trying to wash the curtains every time somebody peed on them to stake a new claim...I took the curtains down and draped sheets over the windows. Much easier to wash. Let them work out their new family order, even though it will involve some tense standoffs. We have a family of 9 cats and a dog, and we all understand that it is necessary to not kill each other. I can't say we don't have cussing and hissing, because we occasionally do still have moments of disagreement. But its not often, and when I holler THATS ENOUGH!, everyone quiets down for the most part. Be firm, be equal and be loving. And best of luck.