It has been announced that for Frontlines players must be in the same Grand Company to queue together on the same team. The biggest issue with this is when you change Grand Companies, your PvP rank is reset back to 0, eliminating all the time and effort you put into ranking up.

This issue is currently being discussed on the PvP forums here along with several suggestions of how to avoid this situation:

http://forum.square-enix.com/ffxiv/t...-in-frontlines

It would be great if switching Grand Company did not reset your PvP rank back to 0