[Ironhawk]

Most of the time, yes. There is one very important case that you must keep in mind tho. In dominions, if you try to move into an enemy province at the same time that an enemy force tries to move into your friendly province, then the computer will randomly pick which province to have the battle in! This could result in one of your forces fighting the enemy on friendly soil, while the other one of your forces continues on to the enemy province unopposed.

As you can imagine this is a very dangerous scenario if either of your forces, alone, is not capable of defeating the enemy force.