since you missed DeadMG's post directly above, i shall re-iterate it.
the Moho Engine used in SupCom/FA DID NOT let you run the game multiple times, even if one farts out some error message all the other instances of the game will spot it and not start.
now, the DG version might now support it, but one only puts this sort of measure in a game is if there's fundemental resources that can't be shared.