How to search PDF in other than physical page order

Question

We need to search a PDF though not in physical sequence - to be positioned at the most appropriate occurance of a term based on the index which we have spent considerable time and effort refining. We are after suggestions and an example on how to address the issue please.  Should we use JavaScript, use the API, consider Indexes, set the reading order, etc.
Our PDF is 1000 odd pages with a Table of Contents at the front and a 2 level Index at the back.  The Level 1 Index are main entries and level 2 indented below each level 1 are secondary entries with additional terms to put the main term in context and allow users to click the appropriate term to be positioned in the document.  eg: a level 1 index entry of "headers" follows with the secondary associations:
headers, 6.10
     see also protective markings
     full stops not used after, 4.7c
     in slides for presentations, 14.25
     spacing at top of page, 6.15b–17
When we do a search, we would like it to search firstly the level 1 Index items, then the level 2 Index items (if possible), then the rest of the document. When the term is found we then need to position both the search results panel (at the left) and the document view panel (at the right) at the location found.
We tried changing the reading order though have only been able to set this within a page.
We tried setting bookmarks for the top level entries in the index, though when we click on the search results panel, it expands showing all bookmarks - not just those that satisfied the search criteria.
We can add html style markup if needed eg DL DT DD tags though this would involve programming to use it ...
If there is not an out of the box solution we are happy to pay for some development.
Thanks, Erica.

Answer 1

not yet answered - though transferred to a more appropriate forum.
thanks.