I might be over complicating this but, when you have different models that can draw different lines of sight to models in a unit is how is it resolved?
Example:
In the example above a USMC fire team is firing on an MEA Infantry Squad. All have LOS to the FZ except for Sarge who is keeping his head covered. in the above not all of the MEA and in LOS to all of the Marines.
CPL: Clear LOS to D, both E and F are in Cover
M249:Clear to A, B, C, and D; E and F are in Cover
M203: Clear to C and D, E and F are in Cover
M16: Clear to A, B, C, D is obscured, E and F are in Cover
Now with the 203 and the CPL not being able to see A or B would their Damage Dice be able to effect those models? Or how would you know whose dice effect which model.
If part of a unit can see part of another and the other part can see the same and more how do you know that the first isn't damaging what it can't see. Or does it not matter.
Example:

In the example above a USMC fire team is firing on an MEA Infantry Squad. All have LOS to the FZ except for Sarge who is keeping his head covered. in the above not all of the MEA and in LOS to all of the Marines.
CPL: Clear LOS to D, both E and F are in Cover
M249:Clear to A, B, C, and D; E and F are in Cover
M203: Clear to C and D, E and F are in Cover
M16: Clear to A, B, C, D is obscured, E and F are in Cover
Now with the 203 and the CPL not being able to see A or B would their Damage Dice be able to effect those models? Or how would you know whose dice effect which model.
If part of a unit can see part of another and the other part can see the same and more how do you know that the first isn't damaging what it can't see. Or does it not matter.