Unit upgrade to be made buyable by allied partner???

Im making an aos style map, and I would like for allied players( humans) to be able to purchase the upgrades for the computer controlled ally? Is this possible? Or if anyone knows a way to accomplish this ?

Actually, yes.

Make a copy of the goblin merchant.

Make the goblin merchant sell items.

Make an item for every upgrade (for example, Computer Plating)

When the item is bought, remove it, and add +1 to the computer's upgrade level with triggers...

Try something like this.

EVENT: (Unit- Generic Unit Event)
Unit - A unit Finishes an upgrade

CONDITIONS: (Player Controller Comparison)
((Owner of (Researching unit)) controller) Equal to User

ACTION: (Player- Set Current Research Level)
Player - Set the current research level of (Researched tech-type) to [Level] for [Computer]

Thanks for the help guys, both excellent suggestions!

ok, I got it working using the first method mentioned, but for some reason when i tell it apply the improved masonry upgrade, none of the buildings get any upgrade?
The troop upgrades appear to be working fine.
Is there something I dont know?
Arent building upgrades applied as soon as the tech is researched?

you need to give the building the improved masonry ability.

and also for the first method you have to make an exception for when the hero inventory is full. To avoid doing this you might just want to make the building sell units.