Preserving File-to-File Text Anchor Hyperlinks When Copying Files

Greetings,

I have a book that consists of a large number of files with multiple hyperlinks that cross-reference to each other. Whenever I copy this group of files, and keep them in their own dedicated folder, these links don’t work anymore and I have to re-make them which is very time-consuming. Does anyone know a way I can duplicate these files but still have their file-to-file text anchor hyperlinks work? Better yet does anyone understand the inner workings of this feature? Reasons I need to do it include revisions to the book or simply to do tests that I want to verify before implementing them on the original files. 

Thanks!