If you have more than 7 players wanting a game, you can play 7 Ages with up to 14 players.
Our group has a total of 10 players all of whom are currently sucked into our current game. Thus 3 of the players have teamed up with other players (me included).
The way we work it is that each person in a team gets one of the two dedicated empires permanently and we alternate who controls the play of the cards (and third empire when we have it) turn by turn. The team mate whose turn it isn't gets first choice of the action markers for their empire and the other team mate then allocates the other (up to) 2 actions for this turn.
You might think that the teams are disadvantaged iin relation to the single players who can run their empires with an iron vill and a ruthless direction. While true you want to team with someone you get on with and have similar playing styles (e.g. empire builder, diplomat or military genius), both players are usually quite amenable to reason (we both want to win after all) and we actually find that often, 2 heads are definitely better than 1.