This was Squad War.
It was a website with a matching system. You register your PXO account with a squad. You either join one or create one. Upon joining, you are counted by the system as a member of play. Admins challenge each other for nodes. If you just started, you can only challenge one of the outside nodes. If you're in, any adjacent node. Anyway, the scheduling system goes for both admins, then the system is in "waiting mode". The website regurgitates a log key. You then meet whoever it was you were to have the match on PXO. You play a normal TvT mission decided on during the matchup on the site. However you tag the "Squad War" button. After the match ends and the stats save, whoever won the match (points based, time limit, etc. how normal TvT missions work.) gets the node.
System had a lot of problems though, more-so when the administration and moderation of it was abandoned.