There is a tree view navigation skin object you can tap into when building a skin which allows you to create a tree view menu system for your DNN site. You can code it to start at different levels / tiers. Thusly you can tell it to start at a certain location and just show all children.

Create two skins basically take your base "Every Page" skin and make a copy of the html / ascx. Name this something like SkinName - WithTreeView really doesnt matter just a way to identify it. Then add in the tree view control to that skin. Then you can tell the page(s) that need the tree view to use the SkinName - WithTreeView skin and the normal pages gets the "default" skin.

That solves the seperation piece, now for the control over the tree view. I will post in a moment I want to look up the attributes to make sure I am correct. I typically don't use tree view so I am a bit rusty.

Ok back, :)

The level attribute will set the root item to start at. Not sure the syntax but I think you can point the level attribute to a page / tab id. I could be wrong though. I will try to find out and let you know if I find the exact syntax.