Horizontal Tabbed Menu

Issue Summary

Im trying to create a tabbed menu like this one;
http://www.filebuzz.com/software_screenshot/full/24241-tab_menu.jpg

My menu structure is this;

Page1
-PageA
--PageI
--PageII
-PageB
--PageIII
--PageIV
Page2
-PageC
--PageV
--PageVI
-PageD
--PageVII
--PageVIII

Ive set my Menu Block parent item to be the root of Primary links.
Ive set the starting level to be the 1st level (primary).

The problem im having is that if I click on Page1, the links are in this order;
Page1, PageA, PageB, Page2.

I need it to be this;
Page1, Page2,
PageA, PageB

So If i clicked on Page A, the order is;
Page1, PageA, PageI, PageII, PageB, Page2,

And I need this;
Page1, Page2,
PageA, PageB,
PageI, PageII,

How can I solve this? Can I get the menu links to be in the order I want or do I need to do some clever CSS work around?

Perhaps I could solve this with lots of Menu Blocks. EG for the 2nd level each Menu Block would have a different top level link as its parent item, the starting level would be set to 2nd, and the Maximum depth would be set to 1 (i think).

The problem with this is that the menu levels, names and content are going to change quite a lot by other authors. Using one Menu Block as I described above and turning off the default menu means I only need to set up one block, if I can solve my layout problem.

I really hope I can fix this as Ive moved from Joomla to Drupal to try and achieve this menu as I heard Drupal was better for managing lots of content.

Thanks