The value of vRtrPimNgIfMaxGroups specifies the maximum number of
groups for which PIM can have downstream state based on received PIM
Joins on this interface.
This does not include IGMP local receivers on the interface.
When this configuration is changed dynamically to a value lower
than the 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.