Alliances, Mergers, and Sub-Companies

I'm the founder of a FC on Cactuar, and I met with a super nice founder of another FC on Cactuar. Since both of our FCs are small, we don't individually have enough members to run an 8-man endgame dungeon, so we create a group together. While we have ways of organizing this outside the game (IRC and TeamSpeak), it'd be cool to have some way to reflect this in-game some way. By way of an alliance, or that we become "sub-companies" of a larger branch, or in the worst case, we merge entirely into one free company without having to manually invite an entire FC's worth of members.

Just a thought on a feature that'd be cool.