Players can access the Crystal Tower via the Duty Finder either solo or in a party of up to eight players. When forming a party, players must first meet the class requirements of the Duty Finder before registering (two tanks, four DPS, two healers). Once registered, players will be matched with a group of 24 players to enter the Crystal Tower.
Not really crazy about this; if you run with a solid group, there's a good chance the 2nd tank (and possibly 2nd healer) are unnecessary given what we've seen groups accomplish in other instances. Until they allow pre-made alliances, I don't really see a workaround.