If no other groups of humans are behaving as rationally as yours is, then it's likely no other humans are capable of easily identifying that your group is the one with the high level of uniquely rational behavior. To the extent that other groups can identify rational behaviors of yours, they will have already adopted them and will not consider you unique for having adopted them too.

You can signal the uniqueness your group by believing and doing things that are both rational and unpopular, but to most outsiders this only signals uniqueness, not rationality, because the reason such things are unpopular is because most people don't find them to be obviously rational. And the outsiders are usually right: even though they're wrong in your particular actually-is-rational case, that's outnumbered by the other cases which, from the outside, all appear to be similar arational group-identifying behaviors and rationalizations thereof. E.g. at first glance there's not a huge difference between "I'm going to get frozen after I die", "I don't eat pork", "I avoid caffeine and hot drinks", etc.