Moving question

By Daices, in Sid Meier's Civilization: The Board Game

If you have two units not together, and you want to attack a city, can you have them meet at the city, or do they need to be together before going into a city to fight?

I was also wondering if army groups can cross over other army groups you have. For example, If I have a stacking limit of two, and I have two flags that already moved, can I go through that square with two other flags together, or is that not allowed because going through that square exceeds my stacking limit for a moment?

Daices said:

If you have two units not together, and you want to attack a city, can you have them meet at the city, or do they need to be together before going into a city to fight?

Daices said:

I was also wondering if army groups can cross over other army groups you have. For example, If I have a stacking limit of two, and I have two flags that already moved, can I go through that square with two other flags together, or is that not allowed because going through that square exceeds my stacking limit for a moment?
:P