Question Making a textured model turn translucent

Hey, so one of my long time problems is that I can't seem to find anything online about turning a single textured object transparent without turning them ALL transparent. Basically; what I want to do is animate them fading to almost invisible when the player mouses over them, then have them pop back when they mouse off.

If it was just a colour, I would modify the alpha channel - but these ones are textured. Basically I'm a little bit stuck. I can change the Surface Type to transparent - but that doesn't actually make it seethrough. It just makes the edges vanish. And I mean the edges for every copy of the object - which is not what I want.

Anything else I could try?