[JustinT]

I know it's been a while since you asked this, but here's another option. If you've only got a few extra people coming in, and you have Aux mixes to spare, you can create duplicates. Use the Copy Aux From function to duplicate your original mix, re-patch your outputs and make the adjustments for the guest performers. Then you only have to change your output patch to go back to the original mix. I'd probably also create new channels for those guests and mute/unmute the appropriate ones per mix.