With IPHost Network Monitor you can run simple snmp requests against a HP device in your network.
hpIgmpStatsTable
hp Igmp Stats Table
1.3.6.1.4.1.11.2.14.11.5.1.9.10.1
A table that contains statistic information about Multicast Groups on any given VLAN on the switch.
Back to hpprocurve-v2-stat MIB page.
IPHost Network monitor allows you to monitor hpIgmpStatsTable on Hewlett Packard device via the SNMP protocol. Download IPHost Network Monitor (500 monitors for 30 days, 50 monitors free forever) to start monitoring Cisco wireless switches right now.