[ HELP ] Dvar Help

Hi Guys, i recently created a thread asking for help with dvar scripting and no one understood what i meant so i will explain basically i want help with so in game on cod 4 if i opened the console and typed message < as the dvar and welcome to the lobby as my value for the dvar and when i hit enter that would then call the script self thread maps\mp\gametypes\_hud_message::hintMessage("Text"); basically like scr_do_notify but so it will do a custom function all i need to know is how to script this via .gsc