Since the 2.5 Attack move doesn't directly allow for a marine to be damaged as a result of failed roll (6-) how does, e.g. a xenomorph's Attack move work?  Do we take turns?

Related: if an enemy wants to Attack a whole bunch of marines in one go should I treat that like the "Solder vs. Group" rule under Force Parity? 

Sorry for the dumb questions - this is going to be my first time running an AW-hack game.