Three against one.

I remember back when there was the third version of Heroes of Might and Magic, I often played against three or more allied computer-controlled armies, because playing against one opponent or against many hostile AI was easy and, therefore, not very interesting. Is there such a possibility in Heroes of Might and Magic V (Tribes of the East)? How can I create a map to play one player against several allied computer-controlled armies? I've seen that such maps exist in the game. But how can I create them myself? Thank you. P.S. I apologize in advance if this topic has already been discussed on the forum; I personally didn't find an answer to this question in the game's FAQ.