I think this will eventually turn into a big zoner group with power, bullying smaller zoner groups with little power under the excuse of representing the majority of the zoner population, when they will actually be representing a minority with power, to preserve status quo and their interests. Just like it happens with factions and skype friendships nowadays and just like it happens in the U.N too; but I could be totally wrong.
I think this could work if whatever policies you implement only affect the members of the union, and don't claim to represent "all the zoner bodies", even less enforcing said policies on non member states I mean factions.