Weird game mechanic.

I don't know if this has been found before, but i found a weird game mechanic in the game. The countries don't capture cities when they just destroyed the unit in it. This is only if the attacking troops are all from one country tho. If two countries are attacking, the second country will take the city. This doesn't work for the campaign, because here the enemy units are divided in divisions, and attack on different points. This may need some extra research, but if it works, then you can just put a weakened unit to save money.