Guest stars don't always have to be working with each other.  They could be rivals on a case.  If Iris, my character, and Keagan, Panda's character, were guest staring with each other, I doubt they'd even think about working together.  Iris may have run across Keagan when she was chasing down her target (who happened to be someone he was also looking for, for instance).  He could have convinced her to stop or sent her on her way or even fought with each other.  (Though I understand if the GM doesn't want to allow such Kincaid-McCoy prestories to complicate the game.)<br/><br/>Rivals, contemporaries, competitors, coworkers, friends...there's alot of options.