Clan Members are able to battle against each other
So within the clan you can pick between the members and attack each other.
With a reputation point system added for fun factor and bragging rights lol.
It would be like a version of the trophy system were you earn status points for winning against clan members. Then your score would be displayed in the clan castle to see who is stronger.
It would also give the less experienced player a chance to practice on each other to see where defences could be improved with out losing any loot.