OK, so right now I'm doing MM and he always opens, then fake a walk away, then back to the set with "so, how do you all know each others?" In his book, he says you must always ask this question.

So twice, I have it happened that the set of girls don't know each others really well. "Oh, we just met. We all moved into this house" and the second time was last night, "Oh, we dont' know each others. We just met about two hours ago."

Usually, i have the best friends test or the C vs Us. But what if the girls just met each others? Is it rude to continue gaming on them, since they are probably trying to get to know each others as well. If I should continue, what kind of topics can be done with a set who just met each others?

It happened to me once, they did not just met but they did not know each other very well, i see no reason why you should eject, you are always somebody who adds to the party, not takes away.