Desaturate MC

Hi all.

Was wondering if its possible to do/rewrite the following as i am completely programming-blind!

Based on the following example
http://www.senocular.com/flash/source.php?id=0.169

I have a movie with 4 (or more) MC’s with an image inside.
When i rollover 1 MC i want the others to gradually desaturate.
When i rollout of it, i want the others to turn back to normal again.
But when i click on one of the MC, i want it to stay ‘active’ , leaving the others desaturated.

Made up a concept for this.

http://img329.imageshack.us/my.php?image=desatpn6.jpg

I know it can be done easily, but i just dont know how to rewrite the example / include this in my movie !!

All help are very welcome !
Thank you in advance