Cross-references to hyperlinks

Question

Hi,

I have document above 3000 pages with plenty cross-references in text added to chapters (headings). I need to split this document to couple smaller docs but these links must still work between separeted docs. This brings me to following problem:
I need to automatically change these links because there is to many of them for manual work.
I know that cross-references do not work with external documents, so I tried to do small tests and replace them simply with hyperlinks by injecting, change REF to hyperlink... whatever I did I hit the wall because the cross-references have bookmarks like _Ref123456789 and do not point location outside the oryginal docx (also the name of it does not say much about location so I don't know how modify them automatically).

How to quickly replace all cross-references to hyperlinks or textlinks or any link with paths to external docs ?

My thinking was to use VBA and do something according steps below:
Having chapter 1.11.1 with a bookmark _Ref123456789 change these type of bookmark to such with name of the chapter it points (in this case would be bookmark with name "1.11.1"). This way I would know which reference should have path to which docx. Insert appropriate paths to appropriate REFs. Replace REFs to HYPERLINKs

If this is a right approach can I get help with such macro?
Please help, Thank You