Panels, menus, and path in Drupal 6
I ended up doing this with the Menu Position module and Menu Blocks module as well as Panels.


Create a Menu Block with

Parent item: 

Menu: Primary Links
Item: &lt;root of primary links>
Starting level: 2nd level (secondary)


Create a Menu Position rule: 

Content Types:

Update

Menu item:

Updates 


Add your menu block as panels content (if desired) to the nodes of the desired type.