Changing the colour of multiple prims

Hello, I recently purchased the scripting recipes for second life book.

I have managed to make the script which opens a dialog box asking which colour I want the object.

However It only colours the main linked prim. All the other linked prims stay the same colour as before.

I was wondering if you had any tips or ideas on how to solve this, so that it paints all the linked prims not just the master prim.

Thanks