The multicast group address which, when combined with alaPimStaticRPGrpPrefixLength, gives the group prefix for this entry. The InetAddressType is given by the alaPimStaticRPAddressType object. This address object is only significant up to alaPimSGRPFRoutePrefixLength bits. The remainder of the address bits are zero. This is especially important for this index field, which is part of the index of this entry. Any non-zero bits would signify an entirely different entry.