I have ideas.
A federation is a group of CW's. Each commonwealth can join ONLY if the leader has a congress hall. You can create a federation with like 100,000,000 civics and a congress hall. You can manage your federation from your congress hall. Leaders of commonwealths talk to Leaders of commonwealths, but if one colony in a commonwealth in a federation has a congress hall and is not the leader, he/she can see the conversations.
There is also Federative Research.
It will add a POINT to joining a Federation. The leader can gather federative research over time depending on how many CW's there are. With this, all the colonies in the commonwealths in the federation can use federative reaserch if they have a congress hall. With this, they can unlock many amazing new technologies. (Federative Techs)
There could also be a building.
Federative Research Lab
Must be leader of federation.
With this, you can see all the federative reaseach your federation has gathered.
I love to give feedback and suggest new things!