Two things here. One, yes, starting gossip campaigns is a form of bullying and a disruptive behavior. Two, next time, either confront the people yourself, or tell your supervisor, but I would not go to the person the rumor is about. That almost makes it worse, because it feeds the drama. That is counterintuitive, isn’t it? It’s kindof opposite from what most people would naturally want to do. Anyway, that’s my take on it. This stuff is tough, and you have a good sense of honor.