1. Go read a book on basic fundamentals on TCP/IP forwarding and what multicast really does.
2. Your network is in somewhat of a mess.
Only solution? Get a better switch that does IGMP snooping. Those switches will block multicast traffic that isn't intended to go there because most cheap unmanaged switches will flood all the ports regardless if there is multicast traffic sent to it. The cheapest switch that I can even think of that does that would probably be a mikrotik.
its not a mess - its been working perfectly well for 4 years - i picked up a DWL-3036 for my network it has IGMP spoofing but i dont know how to configure it.
" Go read a book on basic fundamentals on TCP/IP forwarding and what multicast really does. " i did - the broadcasts go to each device on the network untended or intended - -- My ISP Speedtest »www.speedtest.net/result/2234183999.png