PoppaGator

That's the way they've done it at the ones I've seen.

The "glitch" is putting all the guitars in one hat. It makes a difference if you've got a lot of "backup" chordwhangers and only a few "pickers." If you have a lot of one instrument, you may need separate hats for "styles" for that instrument. You need to put a "lead" instrument with a backup guitar in preference to giving one group a good fingerpick lead guitar and a fiddle, if there's a shortage of an instrument. Fiddles are usually the ones that don't spread far enough for all the groups to get one in my area, although good banjo players are not as plentiful as might be tol'able here.

For impromptu groups like this, someone who knows (and can deliver) a few good jokes to "emcee" the act can be a real asset, but they don't usually have a hat for that.

One session I saw had an "auction" round right after the groups were assigned, where groups could offer to trade with other groups if they felt like the had a "misfit" or didn't get an "essential" instrument. They had a lot of fun with it, but I'd recommend having an "official referee" to block any real stacking of a group that would be unfair to the others. This probably only works if people know each other well enough to tell if the talent is being distributed fairly.

John