Research for the computer...

Let's say there are a group of human players allied with the computer.

What would be the best way for the humans to "purchase" an upgrade for the computer's units?

Should there be a trigger that forces the computer to research it... or a trigger that sets the computer's upgrade to researched..? Or something else?

Im not that good with coding.. so any help is appreciated. :)

The trigger is :
Player - Set researched level of *upgrade* to *level u want* for *the computerplayer*

Regards

How would I do that for something like, say... Defend?

Is 0 = Not researched and 1 = researched?

It would be somthing on the lines of...

Player - Set researched level of Defend to 1 for Computer Player 2.

The level is for spell upgrades such as.. Banshee Adpet Training.. Where there are two sets.. And the armor and attack upgrades.

Thank you very much, you guys rock :D