Hello Marty
Although CGMP is a protocol that will achieve what you need as far as IGMP snooping is concerned, it is best practice to use the IGMP snooping feature rather than CGMP. If your equipment supports IGMP snooping, it is preferrable to enable it throughout your network rather than using CGMP.
Remember IGMP snooping is used to to restrain multicast traffic in a Layer 2 switched network. By default, a Layer 2 switch floods multicast traffic within the broadcast domain, and this can consume a lot of bandwidth if many multicast servers are sending streams to the segment. With IGMP snooping, multicast traffic is restricted to ports connected to multicast receivers only.
For more information on IGMP snooping, take a look at the following lesson:
I hope this has been helpful!
Laz