Netgear GS305E - Multicast Block/Unblock

Hi

I have a source ECU with Multicast traffic, I need to connect it to other ECU (but need to block the Multicast traffic to there). 

I run a short test by sending Multicast packet from one PC to another (both connected to the Netgear GS305E switch), we have seen that the Multicast traffic was arrived to the destination PC, regardless of whether the "Block unknown Multicast" was Enabled or not.

can you explain the behavior, what can we do more to block the multicast traffic to the other ports of that switch ?

Thanks!