dynamic side menu

hey all,

I’m trying to find a way to dynamically alter my pages side menu. What I want it to do is to show my sub-pages when the corresponding main page is highlighted.

Basically explained:

I want to see this when MENU ONE is selected:

Home
Menu One
*sub One/one
*sub One/two
Menu Two

…and this when MENU TWO is selected:

Home
Menu One
Menu Two
*sub Two/one
*sub Two/two

I am using the wp Andreas 01 Theme and figured it had something to do with the depth attribute of the wp_list_pages function (i have it set to three right now to display al subpages and sub-subpages)

Any help would be super!

kind regards.
T