How can I block/Firewall HA from probing my portable radio (Internet/DNLA)?

I just bought a new radio and unfortunately it’s smart app loses connection every few seconds when HA turned on . Another poster on another ha forum suggested I move the radio to another subnet so Ha could not see it. That worked but it also stopped the smart app from working because it runs on our phones on our main network (192.168…11.x)

Is there a way that I can firewall a single IP address on our main network so HA can’t see it?