The value of vRtrIgmpGrpIfMaxGroups specifies the maximum number of groups
for which IGMP can have local receiver information based on received
IGMP reports on a SAP belonging to this group-interface. When this
configuration is changed dynamically to a value lower than currently
accepted number of groups, the groups that are already accepted are not
deleted. Only new groups will not be allowed. When this object has a
value of 0, there is no limit to the number of groups.