Upgrading unit individualy

[gex]

How to make an upgrade that upgrades each unit individualy? Each unit has "upgade used field" and "researches available" filled with the same research so each unit has this upgrade on self.
What I want to make is that when I select that unit and click that upgrade only that unit upgrades. Can this be done with only custom upgrade(without triggers and custom abilities)?

 

[shadow1500]

you will have to make custom upgrades for each unit that is in your map, and then the unit will be able to upgrade himself.