The List of a Radio trigger is empty when activated, so I basicly assume that this method does not work.
I have an old method using two triggers, a Delay, and a two Public Variables that can tell you who activated it.
On a side note, the application I used it for ended up resulting in INSATIABLE amounts of LAG for the server computer, to the point of AI (no matter their skill) becoming as stupid as one can get, including reaction times of up to 1 full minute.
Needless to say, I need to look into that a little more.
I'll probably post the procedure in about a day or so, when I get home.