Can you hide an upgrade

[roaaaarrrr]

I dont want an upgrade on a building to be available until a certain point in the game. If it was a regular ability, I know I could just hide it for the time I wanted, but I cant find how to hide an upgrade. Is there a way to do this or another solution?

 

[Xan_Kriegor]

It's a ghetto way to do it (as in, probably a million ways to do it better), but if nothing else you could make your upgrade take another upgrade to research, and then just after however many seconds into the game have a trigger research the prerequisite upgrade for the player.

EDIT: The player(s) will still be able to see the upgrade, just not be able to research yet. Just to clarify.