I was once on a netball team with seven Lauren's and a Lisa. (seven on the court) My coach spent the first two games dying of laughter before we got it all figured out. Combo of nicknames for Lauren (I think we had L, Liz, Lozza, Lozanger, Lo and two last names) and positinal terms (instead if yelling out 'Lauren here!' it was 'centre here') but we got it in the end.
Well, I was the oldest, so I was "Big Chad". The next oldest played with me for several years, so he had been "Little Chad" for some time. (Although, I was the only player bigger than him). The rest either got nicknames or called by their last name. The coach had no problem, but I hear that watching the parents cheer or jeer during the game was a hoot.