Select 2 out of 3 gameobject before doing something.

Hi guys, I'm new here.

Basically a newbie, I'm trying to get simple project of mine to work. Part of this is what im asking right now.

This section of the game involves selecting 2 objects out of 3.

There are 3 objects, lets say cubes, cube 1, cube 2 and cube 3 fairly distanced from each other left to right. You need to select 2 of them before proceeding to the next part.

Choosing 1 will not do anything since you need two to be selected. Each cube combination will produce a different result. Lets say, if you choose:

• Cube 1 and 2, you get shown to Game over page.

• Cube 2 and 3, lets you proceed with the game

• Cube 1 and 3, restarts everything.

Lastly this is touched based, since I'm doing it for android. I'm unsure which is best, OnMouseUp? or will ray casting work? I have no idea right now, since im doing the other parts of this project.

need help

thanks guys!