I think the main question is how would you be dispensing it at the party? If your using a regular party pump I think it may get oxidized. I had a friend who had a keg of Coors for her wedding, invited us over the next day for a "keg killing" party, and it was obviously oxidized.
If you can put the Coors on CO2, you could dispense it directly to the cornies (i.e. liquid out from Coors to Liquid out on cornie). Then you could divide it up to the cornies before and dispense normally, and they would all be untouched by air, just on CO2.
But, that means you would need the adapters and such for the 1/2 barrel. You should have time to order them if it's the weekend of 9/13. Might be nice to have on hand anyway
That's all I've got though.