Displaying different page links on different pages

I think you may be making this more complicated than it needs to be.

  1. Use custom meta fields to associate the different pages. You could
    use the built in “Custom Fields” meta box or build your own meta box
    for this “association” field. Populating your sidebar is then a
    matter of a meta_query.
  2. Use tags to associate related posts. Populating your sidebar is a
    matter of a tax_query.

Whichever you use, you would only need one sidebar widget to pull the related posts.