With all the modules you would have 6 different force and break that down by Infantry, Mech, Armor you have
US - 3
US Marines - 2
Brits - 4
Canadians - 3
German - 3
Dutch - 3
Thus you could have up to 18 players on the NATO side.... so you could create an OOB, for each one of those, and then as people join they get their choice of what 'units' they command... gives some scalability as it goes along...
Now on the Syrian side not sure what you have created but the same could be done... Needless to say they would need a 'bonus' advantage to be competitive...
Just babbling....
Anything I could do to help Bootie, just ask...