With IPHost Network Monitor you can run simple snmp requests against a IBM device in your network.
ifHCInMulticastPkts
if HC In Multicast Packets
1.3.6.1.2.1.31.1.1.1.8
The number of packets, delivered by this sub-layer to a higher (sub-)layer, which were addressed to a multicast address at this sub-layer. For a MAC layer protocol, this includes both Group and Functional addresses. This object is a 64-bit version of ifInMulticastPkts.
Back to ibm_mainframe-Ifmib MIB page.
IPHost Network monitor allows you to monitor ifHCInMulticastPkts on IBM device via the SNMP protocol. Download IPHost Network Monitor (500 monitors for 30 days, 50 monitors free forever) to start monitoring IBM switches right now.