Grey Templar wrote:does it specifically forbid them from joining?
unless it does, i would think they can just use the normal Kamphgruppe rules.
Nothing forbids that specifically, but it is somewhat different. Panzergrenadiers are allowed to combat attach the individual guns out to the infantry platoons, meaning that each of the panzergrenadier platoons can have one or more
AT guns attached to the platoon. Grenadiers don't get that option.
I don't know the exact reason behind it, but I would imagine that it's supposed to portray the way that the combat doctrines worked between the different types of formations. The
SS Panzergrenadier box that Battlefront sells even comes with 7.5cm PaK40 guns to combat attach out (and machine gun crews as well - mortars and half-tracks need to be purchased separately) as well as the basic infantry platoons.