First of all, I would like to apologize for the lack of pictures that would doubtlessly help you understanding the situation better; I don't have any external capturing software and Age of Empires II just wouldn't cooperate with me nor would it behave, but I will try to explain the overall battle as much as possible and, hopefully, it would be just as good as a series of pictures :P
So... my friend and I made this gigantic map for Age of Empires II: The Conquerors which basically consist on large city inhabited by a neutral player and that it's currently being fought over by a Red Army (1555 units) and a Gray Army (1750 units). The starting positions for this particular map have the Gray Army occupying about half of the city and surrounding it with the rest of its troops, while the Red Army is in control of about 75% of the city and the area behind it (which is a shipyard connecting to a lake that surrounds the entire map).
With some practice I managed to drive the Gray Army away from the city and I even found a way to make a diagonal corridor in which I could hoard my soldiers and artillery pieces to deliver a point-blank blow to the enemy forces that were surrounding the borders of the aforementioned city, but the computer took notice of it and completely decimated my army there, right to the point of making me withdraw whatever I had left back to the fortress.
Now, my problem is that I'm down to 864 men (including cannons and other such pieces) and the computer no longer tries to break thru my positions, but it instead has decided to concentrate its troops nearby in overwhelming numbers. Questions is: What should I do to lure it into attacking me where I'm strong? There's no way I'm going to survive a head-on assault against an army that it's both numerically superior to mine and that still has many of its most powerful weapons still intact.
The player that is an allied to us both has build many strongholds and the like all over the map, so I think that if I somehow manage to turn it against the Gray Army, it would be enough to weaken it enough for me to attack, but I have no idea how to do that.
Anyway, that's the situation guys. Any ideas on how to solve it? :P Thanks!