You know since everybody always goes in teams, why not make a tribe menu? Recruit tribe members for the game while you play so you can't hurt teammates until the game ends.
I would think if one tribe wins, then it will start the next round, instead of forcing the tribe to fight against each other.
It'd most likely split up like a couple people collecting resources, while a couple of people are well armed and defending. If they become the last tribe standing, the miners won't stand a chance.
It'd be best if you're working AS A TEAM, you should WIN as a team.