NAP button,or Ally button.
Aim think that its will be interesting that you have option in game to become Ally with some other player,and from single transform to double game.
Examle-3 player game,one oppponent is much stronger then other two,and these two decide to become ally,press ally button,and then opponent can each other to give armies and fight together for points.
example 8 player games start single,in some moment some player start creating alliances,and from single game become double,triple game.
Ofcourse some limit must exist for activate these option,after 10-20 or 30 rounds.
These can be very interesting to see.
I hope that you understand what i sugested.
