Correct multicast routing

Hi,

Can someone explain, how to route multicast streams on local network corectly?
Only from one lan interface to another, no other needs. Right now without any rules configured, it streams for all lan interfaces.
Multicast streams comes from local device, not from WAN side.
Router is: CRS109-8G-1S-2HnD-IN
Multicast stream device is connected on ether3-slave-local interface and needs to be routed only to ether4-slave-local.

Thanks