Ranking a revolving average?

I'm working on an archery league spreadsheet, and have a problem:

My league is set up where one team plays against another team each week. The tricky part is that the player with the highest average plays against the other team's highest average player. Then, the middle averaged shooters play against each other, then the lowest average shooters play against each other.

The average is figured every week, so the high/mid/low shooter on the team is constantly changing.

How do I write a formula to decipher who is the best shooter on each team, who is the mid, and then who is the low shooter on the team each week?

This is my first question of a series, but this answer may take me to where I want to go eventually.

Sorry, I think I'm missing the bit about how many arrows you shoot per round/how long you're aiming over.

The short answer is =average(cell1,cell2,cell3) or =average(<select a contiguous range>) but exactly how to apply it would require you to upload an example.

HTH