I think when playing the Germans in most east front games then ZOC is always a consideration to play if not the main one.
Here is the situation in my current game of Moscow 42 playing the Rzhev scenario Jan 6th - Jan 9th.
The Russian player advanced over the river but because he has units which easily disrupt then it becomes possible to push him into isolated pockets and sometimes destroy them. I've managed to destroy one group south of Yelt'sy and isolate his units at Yelt'sy. I'm not strong enough at Syl'kovo but I think he realises now the risk in advancing there.
I've got hotkey running so I'm using the the blankbox.bmp with the short cut reminders on until I can memorise them.