[ask] wall color changer

Hi,I'm a ne member here. My name is Lim. I kindda a new in flash. So I have this problem. Let say I have one picture. In that picture have two walls. Left wall and right wall. And I have 3 colors (red, blue and green). What I want to make is a color changer demo. So whenever I want change the left wall into red, I click red, and when I want to change the right one with blue, I click blue and it change into blue color without changing the left one.
I only manage to made the whole change its color, so if click red then the left one and the right change into red. If click blue then the whole wall change into blue.
I just wonder if there any way to do this?
Thanks.

Sorry I forgot.
This is the file I've made

http://host-a.net/lim/test.fla