I'm GM'ing two different groups one is playing Hell's Rebels, while the other is playing Hell's Vengeance, and I'm looking for as many crossovers as possible. Not direct confrontations, (trying to avoid player deaths), but easter eggs, or times when I can have them interact, such as the ball in Hell's Rebels. We're all friends, and having cross-overs once a book or so could be a lot of fun. Any ideas?