[Ozuru]

The grammatical issues in your post make it quite hard to understand what you're asking, is there anyway you could clean it up?

I think you're saying that there are 3 viable team captains and you're asking how they should determine who will be the team captain. (?)

The way that our team (and many other teams) choose this is through having a democratic election where individuals of the team vote for who they would like to be the team captain. If you'd prefer it to be anonymous, just simply have everyone write down who they'd like on a piece of paper and tally the votes.