Perhaps it'd work if it was some hybrid between pug.na and mix, say under normal circumstances it acts more like mix where it can alternate between mixes and pickups.
On the side players with permissions (read: Invite players) can add up to a special pug and vote for a non-League map to be played on later on. When it's around 9 or 10 pm Eastern these players can check-in and if the system determines that there's enough players to start an xPug, then it'll open the registration to all players that want to pug.
So here's how it'd break down: Each team would have an invite player captaining and 2-3 Invite players per team with the rest filled in by everyone else (even numbers and ideally even classes), then the captains receive the result of the vote and can choose to either accept the result or override it for another experimental map.