How to search PDF in other than page order

Question

We need to search a PDF though not in sequence. We are after suggestions on how to approach 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 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, then the rest of the document - and position both the search results panel and the document view panel at the first location found.
We tried changing the reading order though have only been able to set this within a page.
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.