Enemy cities negate supply ?

[Franciscus]

Hi Ron

I noticed something that probably is intended but is not clear from the supply rules.

Enemy held city hexes with railroad, without any enemy unit in the hex or adjacent, even with adjacent friendly units,  negate the flow of supplies.

I presume this is intended, because it works like this in MDE game. But it is not mentioned in the WWIIE rules...

Regards