Best way to collaborate on paper without sharing library

Another thing I was wondering - what is the best way to work with another author’s references without having to ask them to share their entire library with you.

Here’s my example. I’m working on a paper where the primary author has put references in that should be joined but he has put a space with them so Endnote doesn’t recognise that they should be together. I tried deleting the space and updating the bibliography but they didn’t join. So I unformatted the references and manually joined the temporary citations. But of course when I went to format the bibliography it couldn’t match up the references with my own library.

Then I tried exporting a travelling library and formatting the references from there but again it didn’t work - I had to match each reference because they all had different record numbers.

So I gave up. I really wish there was a better way of identifying references than record numbers, they always lead to problems when collaborating. The new sharing features are great but not everyone wants to share their entire library with you.

deleting the space and updating citations and bibliography, should properly group the citations.  

Added in edit.  

This may confuse the collaborator when you return the document, but if you export the traveling library, and update the citations in the document, with that traveling library open, it links to that version.  - you can unformat and reformat with that exported library.  – Also you can change your preferences, to use page numbers and this might be invisible to him.  It is all in the order you do these steps.