I want to create many pages and subpages, possibly even 5 levels deep. Navigating this through a drop-down does not really make sense so I want navigation of the pages in sidebar.
Now the widget (or whatever else method I can use) cant very well show all pages because it would be huge. What should show on each page is children to that page (1 level), siblings, parents and parents siblings (all except top level). see http://www.reactgroup.org/who-we-are/organisation/regional-nodes/react-latin-america.html to see clearer what I mean. (you can see that pages hierarchy: one child, one sibling, its parent has three siblings and its grandparent two siblings.) This type of navigation is quite common on complex sites and gives a good overview of where you are.
I dont even know where to start with this. I have scanned most plugins but none of them come very close to this. Is it even possible in wordpress?