MMRP is supported in B-VPLS instances over all the supported BVPLS SAPs and SDPs, including the primary and standby pseudowire scheme implemented for VPLS resiliency.
When a B-VPLS with MMRP enabled receives a packet destined for a specific group B-MAC, it checks its own MFIB entries and if the group B-MAC does not exist, it floods it everywhere. This should never happen as this kind of packet is generated at the I-VPLS/PBB PE when a registration was received for a local I-VPLS group B-MAC.