Enable/Disable upgrades using triggers

[DwarfBoy]

So, I had this idea for a map I'm working on where the player can chose 2 of 5 different units. However, for this idea to work, I need to be able to enable and disable upgrades using triggers. Is there anyway to do that, or is it a hopeless endeavor?

 

[WaterKnight]

Player - Set Max Reearch Level

or set a requirement for the upgrade in object editor.

 

[DwarfBoy]

Yeah, I know. I just figured it out.