I read series back in the late 90's and loved it but can't remember name or author. Basic storyline was a group of humans (not friends beforehand) get transported to a different world or time and have to learn to adjust. As they spend time in this magical world they begin changing and taking on magical characteristics themselves on a genetic basis. For instance, I know one female character ends up becoming a succubus. I believe one of the males becomes a giant or minotaur, something strong and warrior type. I know it was a series...maybe a trilogy. Any ideas?