Specifies the forwarding policy applied to private forwarding group B within this PFG profile -- the counterpart setting to group A's policy but scoped to whichever ports/services are assigned to group B. Like the other group policies, it has no practical effect unless the profile's private-forward-group status is turned on, so it can be pre-configured before that toggle is flipped. If group B here is set to isolate its members while allowing flow to group C, ports placed in group B won't see each other's broadcast traffic but will still see group C's.