Give guilds the ability to challenge one another. If two players from different guilds could talk to one another and agree to play, those two players could each form a team and become “captains”. One of those captains could then send a challenge akin to a trade request to the other captain. Once the challenge has been accepted, teams could fill up their respective rosters and play one another.

I think guild Lockdown play would increase quite a bit with this option. I know I’d be much more willing to play if it was against friends and I knew I wouldn’t be waiting who knows how long for another team to form.