[SG2] Combining support weapons in a single fire action

SG2 as written doesn't allow you to do this. However, poking through the US
M249 SAW Field Manual, I see them describing engaging targets with a pair of
riflemen. See:

http://www.adtdl.army.mil/cgi-bin/atdl.dll/fm/23-14/fm231_7.htm#REF67h3

I've got an assault squad with 2 SAWs - it's 4x Shotguns, 2x Flamers, 2x
standard SAW, all in full suit armour.

When firing past one range band, we've always just done quality + 2 SAW
FP die (can't remember what that is right now!) and it works fine.

Theoretically, the plan is to use the DET rules to split off the two SAWs and
have them in support while the rest of the squad enters close assault; in
practice I tend to send everyone in regardless...

Having two different support weapons is harder to manage, but I like someone's
idea of using the FP die that rolled higher to determine which Impact die to
use.

My $0.02,