Tree Store for layers

["David Conley (FRD)" <dconley frd co uk>]

I'm hoping to use a tree store/view to create a layer typer system where 
the higher up the tree an object is, the closer to the front of the screen 
an object would be. Imagine the layers in Photoshop or GIMP for an idea 
what I mean. Is there any way I can get that kind of information from the 
widget? I'm using C++ if it makes any difference to the answer.
So to recap I'd like to get a value that says:

+parent
+-+sub menu
+-+-sub menu 2 <-This menu is higher up...
+-+-sub menu 3 <-..than this menu

Thanks
Dave