making an invis prim not touchable

I am working on something where I hide and unhide part of a hud. I would like to find a way to keep the transparent part of the hud from intercepting touch events when the user is clicking (as the user doesn't see the prim and is trying to click on something the transparent prim in the hud is over). Imagine a hud the size of your screen but set transparent. I would like to see how to keep all touches from being eaten by the prim. Any bright ideas? Barring that, any easy way to get about 20 prims to go away and pop back to where they were (in a hud ) - like all hide in the upper left corner and get real small so they dont eat touches?

You could have it pass the touches onto the rest of the object when invis, and have it send a specific message or something.

Also, for the moving it out of the way, method, I believe llSetLocalPos() will work. If you wanna shrink it too, then llSetPrimitiveParams() I think has that capability.