[TYPO3] active menu item sort/ display active menu item first

[Kathryn Blair]

Hi everyone,
 
I hope you can help me out with this. I am a TYPO3 n00b, but I've been
trying to find an answer for my question - unfortunately I'm not sure if my
approach is at all correct so it's hard to search for the right keywords.
 
Anyway, here's what I need to do.
 
I have a site with four different sections. Sections are organzied in a tree
structure. When one is within a given section, I want the navigation for
that section to appear at the top of my menu.
 
Here's an illustration:
 
Back end page structure:
* A Section
** A Page
** A Page
** A Page
* B Section
** B Page
** B Page
** B Page
* C Section
** C Page
** C Page
** C Page
 
When viewing a page in section  C, the menu should appear like this: 
* C Section
** C Page
** C Page
** C Page
* A Section
** A Page
** A Page
** A Page      
* B Section
** B Page
** B Page
** B Page
 
And for sections A or B, the A and B sections should be on top. 
 
I approached this as a sorting problem (Ie. first the menu should sort on
state, then on backend order (sorting)). But because alternativeSortingField
works on fields, I don't know how to sort based on state - it's also totally
possible that a better way to do this exists that has nothing to do with
alternativeSortingField, I just wouldn't know what that way is. It did occur
to me to make distinct menus for each section and order them manually, but
I'm designing the site for other people and they won't be able to add more
sections after I go if I do it that way.
 
If this is at all possible, please let me know. If not I'll just have to
hard code the order. 
 
Thanks a lot. Sorry if this is a n00bish / ridiculous / irritating question
-- I tried to find answers but I couldn't find any answers that I thought
I'd be able to adapt to work like this on my own.
 
Kath Blair