[support] Menu Shennanigans - Hide parents & their siblings (yep, I'm confused too)

[Rob Wilmshurst]

** Apologies if this has been sent twice; my mail has been up and down 
all day **

Howdy-ho,

I've got some subsidiary pages that all belong to a 'Subsidiary Links' 
menu.  Something like:

SUBSIDIARY LINKS
--About Us
--Contact Us
--Environmental Responsibility
----What we do
----How can you help
----Al Gore
------Al Gore!  Al Gore!
--Drive More SUVs
--Nuke The Whales
--Just Kidding

Anyway, you get the idea.  Rather than show this entire menu on every 
subsidiary page (there will eventually be a *lot* of these pages, I'd 
like to just show the current branch and its parent (going down as many 
levels as required), hiding the parent's siblings:

Environmental Responsibility
--What we do <<-- CURRENT PAGE
--[snip]

Erm, how is this done?  I've looked through the API and it's pretty 
incomprehensible (to me at least) how to do this programatically.
I've also tried the menu_trim module, which goes one step too far and 
loses the parent link (the only way to get 'back' to another section).  
I tried fiddling with the menu_trim module (specifically, altering its 
trimming to start at the parent, not the current item), but that 
unleashed hell and brought out the parent of the Subsidiary Links menu.  
Argh!

Thanks for the help,

Rob

-- 
Rob Wilmshurst
drupal at fifteenoclock.com