When using groupRadio, sideRadio, globalRadio, I use actors that are far from the battlefield so that I can control better the flow.
I noticed that I can't hear the messages even though the sound files are properly recorded and declared in the description.ext.
In a nutshell: the text is broadcasted correctly to the right channel but the audio is spoken locally, as if on directSay. You can hear the radio squawk but if you're too far away you will not hear the message.
NOTE: also kinda breaks vehicleRadio, it'll be muffled. {F26501}