[gmw]

I am not aware of any way to do this with kindle or epub books.

Even if some particular device were to support it in theory, those links would be unreliable for the files on different devices because the files are stored in different ways (imagine trying to link to a particular file in Calibre - it makes up its own directory and file names). Added to that is the problem of linking to some particular location inside the book from outside the book, I'm not aware of any way to do that reliably either; it would require support from all epub/kindle reading software. So I recommend that you don't even try to do this. If external resources are absolutely essential, direct to a website - this is well defined and portable.