What should we all do about this?

OK, so on Friday I have a little excursion with school where we all have to be in groups of 5 or 6. My friendship group is 10 so we're all okay so far. Only problem is, we were originally two separate groups. Me and my best friend are at a loss of what to do because nobody wants to be left out, and we're thinking that if we split into the two originals there will be no dud group and no conflict during the day. But we're pretty sure that the others will want to mix it up, resulting in a dud group and lots of conflict because not everybody will be happy with their groups. We keep asking the girls what we should do but they keep dodging the quesiton. What do you guys think?