You may want to have a look at:
- `MovieStar Spain Fiber Modem Move Internet and IPTV to AX3
- The complete SSDP + mDNS solution for network segmentation
topics for hints. Tough instead of IGMP Proxy and multicast querier (on the router as used in the first one of the above two suggestions) using PIM-SM as described by @DarkNate is a better practice.