Unique Sidebar Menu (page by page)

Hello,

I’ve searched the support forum and couldn’t find anything related.
I’ll try my best to describe what I’m trying to do.

I would like to have a unique sidebar menu/nav that displays only the sub pages of a top-nav category. An example of this kind of menu could be found here.

http://www.macquarie.com/mgl/com

When you click Company Profile it builds a sidenav of it’s subpages and if you click another top-nav category it would build it’s subpages etc.

Thanks in advanced!

TK.