Aha, I see now.
So if the hardware uses the standard DX mouse inputs then in theory GG would pick that up as an x,y screen position plus a mouse button press. Assuming that bit all works correctly then yes what you want to do is doable.
You would need to use the same mechanism for mouse detection as used in small's inventory script and on mouse 'click' use the x,y mouse coordinates to work backwards and calculate what object is 'targetted'.
That final bit will not be a walk in the park btw, you will need to calculate, based on current field of view setting, what the 3D vector should be based on the x,y values, then project a ray in 3D space from the player to detect which object, if any, is hit.
Edited to add: This is something I would be quite happy to help you out with assuming I could get access to the hardware, do you have a link to it?
Edited to add: Found the device, bit expensive and no technical details on the link I found so I can't tell whether it would work with GG, I'm guessing the answer is probably no.
Been there, done that, got all the T-Shirts!
