Trackback from Ars Ludi arsludi
For damage purposes how might we approach a "gang"
One possible solution.. give the gang a single amount of resistance to attack. (Hitpoints, Toughness etc.)
This could be the sum of their hitpoints (D&D) or a combination of their Toughness modifiers (constrained in some way).
For D&D - giving the gang a set pool of hitpoints means that very effective characters can damage the 'gang' beyond damage to an individual. So if a gang of 10 kobolds has 30 hps (3x10) and my ranger does d8+6 damage an attack, he would slice up the gang in a few hits (3 on average) rather than needing to kill each kobold directly. You could rule that "gang kills" this way are actually just disrupting the gang (which could reform outside of the combat) unless the number of hits equals the number of creatures in the gang.
For M&M - The system has lots of ways to accomplish this with Hero Points (spend a point to get a rank of takedown)(make an alternate power with area of effect).