[Baron Spikey]

Example:

You have 8 Marines in a Tactical Squad.
1 Vet Sgt
1 Heavy Bolter
6 Bolters

You get shot at and 8 wounds are caused. You have to roll for your Vet Sgt & Heavy Bolter Marine separately from the 6 Bolter Marines- if there was a variety of weapons that hit the squad you can choose what hit who (so the Vet Sgt was hit by a lasgun rather than a lascannon) but you no longer roll all your saves and take off which ever models you want if say 6 saves are failed.

Is that at all helpful?