Unit Control Groups

Is there a variable which allows you to manipulate these?
I mean the ones which you use with ctr+<number> to set and <number> to select.

No, as far as I know the control groups cannot be manipulated by triggers.

Ah well... :(

There goes my idea of checking if those units were selected to detect if the number keys were pressed.



..If anyone knows a way though, please share. :)