You want to "break" the limit of 12-unit per control session at a time mechanic ?
I don't know if you can "break" the limit or not but we do have method that would "increase" the amount you can "control" at a time, it's called Squad System or Battalion something.
Where 1 unit will act as "head", and other unit can "follow" under this "head".
Where "head" moves, "follower" will also move to the designated location.
You still have a 12-unit maximum control per session BUT under these 12 units, you can have as many units as you want for it to follow.
Basically you'll be having a maximum of 12 "heads", but limitless possibilities of "follower" per "head".