unforuntately i have to agree with everyone else on here in saying that its a weapon type that pins, not individual weapons of that same type.. i do have to agree however, that if there are different TYPES of pinning weapons (ie. a barrage weapon + a sniper weapon, or a sniper scout squad lead by tellion) in the same squad, it would require multiple pinning checks (as tellions weapon is different from a sniper rifle) if that weapon type causes any unsaved wounds during that units round of shooting.. in this example two.
another example is a chaos sorc. with lash leading a squad of noise marines with a blastmaster. lash doesnt cause any wounds, but would still have to take a pinning check at the end, while the blastmaster if it causes any unsaved wounds, would have you take another pinning check. would you agree you would have to take two pinning checks? i would..
atleast thats how i see it and would rule it..