How to hide a part of a GUITexture that rotate ?

Hi,

Trying to design a small airplane game, I’m now facing a problem I don’t know how to solve…

I want to add a king of altimeter instrument with on a side (green thing) the altitude value, and on the other one a graduated circle (red thing) that will rotate to simulate a real instrument (without graduated values). I was thinking about displaying only a part off this GUITexture maybe using alpha properties but I don’t know how.

Here’s a screenshot of the game to give you a better idea of what I’m trying to do:

Finally decided to change the way to do it so now it looks like this :

so this way I can just rotated the graduated wheel behind the main instrument Texture :wink:

Anyway thanks to moghes for your help !