Improvement Request for EndNote 20

I am trying to simply attach files to Endnote references. No problem to do one by one, but what if I have multiple Endnote references that require the same PDF attached to them (like multiple chapters in a book, in which I only have the PDF of the entire book)? It would be great if I could select all the multiple references and attach that PDF in one step, instead of having to go through and attach the PDF to each Endnote reference one by one.

This would be a great improvement to future versions of Endnote.