umm, not sure bout the hitchhiking, but 4 the text on the radio rather than alpha, bravo, ect.
When U make the radio trigger, find the "text" bt and write down what U wanna appear on the radio
to make them appear on certain conditions, jus goto the conditions bit and get rid of this and put down what conditions U want (eg !alive player if U wanna see if the player is dead)