Looks good, the abbreviation in parentheses really helps.
As for the Army Group, no need to 'explain' it really, rather thinking on it, just putting the symbol next to the instruction would make it crystal clear. As in:
"All GMD Commanders
Attack USA Support
And Their Own
Army Group <put a miniature blue box with 'X' here>"
And similarly, put a miniature red box with an 'X' in the CCP set of instructions.
Anyway, I'll take silence for consent that this map is good to go. Barring any further comments, I'll stamp this tomorrow.
-- Marshal Ney
EDIT: It's tommorow

Oh and btw, I didn't say but your explanation of Army Group was good, just gave the above suggestion if you wanted to save space.
Congratulations Industrial Helix

Hopefully this Red Invasion will revolutionize the CC masses and... well, you know the spiel.