Help Me pls i want make a Radio Chat but i don't know to make this

Hey !

I'm trying to make a radio system (CHAT) and i have make /radiofre 150 and a other command for set a name on the radio /radioname Lucas but how I can make a command to make if they are on the same freq *and if they have a radio* only they can see the message send ?

If somoene can help me that could realy be nice !

Thanks you !