Eastern front and Warsaw questions.

[VonWulfen]

Hello all.
Could anyone explain the rule that says 6 units must stay within range of Warsaw once captured? (I am playing as axis)
What size units do I need to station there and what is the most economical way to achieve this?
After taking Poland I started moving troops to the western front. I am now ready to move on France but am worried about the buildup of Russian troops in the east.
Is it possible to go against history and concentrate on the eastern front first? I would like to try and take out Russia before pushing into France at a much later date.
Edit; I just noticed on the War Panel that Russia has endless morale. Does this mean they cannot be forced to capitulate?

[AlvaroSousa]

6 divisions will suffice.

I the new patch the USSR surrenders once you take ALL their production and manpower/morale urban areas.

[VonWulfen]

Many thanks, sir.
Is that the upcoming patch?