It does sound like a good idea that somewhere there is a list of who is in which faction, that everyone can see.
I have discovered that despite my Mod powers I can only see my faction list under 'Usergroups'.
Just a thought: is it possible to add a 'note or mark' of some sort to the signatures, or in the user title area?
Otherwise you are looking at a way of the usergroup list transferring, and updating itself, to each of the faction forums somehow, which would then limit each faction to knowing their group only.
On a second note - the admin/mods who are going to participate: they will have access to the 'other' factions so are on trust
not to go spying.
Whilst I imagine we are all honest upright figures who would not dream of sneaking a look at the other faction plans, is there a way our powers could be barred from the 'other' factions' forums?