Question: simultaneous movement

[Dogboy]

What determines where battles will occur if two armies move past one another? I realize that friendly movement occurs first, so let's assume both armies are moving into enemy territory.

Can a single team A commander in Team A province 1 move into Team B province 2 and stop a large team B army from moving from Team B province 2 into Team A province 1?

How about a commander in Team A province 3 moving into Team B province 2 -- can he stop a Team B enemy army moving from 2 into Team A province 1?

How about a stealthy commander in Team B province 2 who comes out of hiding to "attack province"? Can he stop the army in 2 from moving into Team A province 1?

I've seen several discussions on the topic, but no resoultion, and nothing in the FAQ as far as I could see.

Thanks!