i.e. when I turn a knob or pull down a slider it affects all the groups equally.
I've spent 20 minutes on this, am losing the will to live
TIA
Sounds like you have all groups selected (highlighted) Shift + Click a single group and you should be all set!
On the controller, press "Select" Make sure "Multi" (Button 8) is selected and press a group pad. Turn off "Multi" if you want to only select single groups...
The mixer has reverted to Groups now all on its own, but thank you Blindeddie.