At the moment, only Tatty has contact with our negative cats. After he was neutered, and had lived indoors for several months, he calmed down considerably, and over a period of several months, he got used to sharing a house with people and other kitties.
Tabs has joined us much more recently, and we are still in the very early stages of attempting to integrate him into our family. As both he and Tatty are FIV+, we thought we would start those introductions first. Unfortunately, even though Tabs started out being a much calmer kitty when he joined us than Tatty was, he has shown signs that he may not like other cats.
I'm not giving up hope yet - we still have a long way to go.