Pretty sure I've suggested this before, but I'll do it again. Could the restriction preventing you from inviting someone from the other opposing faction be lifted if the leader is already in the Cimerora zone? It only happens if one or more invitee is out of zone, and makes absolutely no sense.
It makes forming a team a royal pain, when you have 1 or more out of zone, and several players in zone pinging you for an invite.
I wish more players knew about lfg queing into the zone, but apparently a good 90% of the population has no idea about it, so this remains a big issue for someone like me who does the ITF quite a bit.