Thanks for the help mousetrap!
I have another question, how would I restrict these actionmenu items to two units? I've tried the following in the i_client file with no success.
GVAR(action_menus_unit) = [
[["FAC", "FAC2","FAC3"],"Call Artillery", "artillery.sqf", -1000]
];
The units FAC - FAC3 don't have an actionmenu option, what am I doing wrong? I'm assuming the FAC - FAC3 are the Names: for each unit.