Export sublibraries with parent library (with de-duplication)
I have a shared group library with many different sub-libraries. I'd like to export the entire library at once (NOT my entire collection) to put into a BibTex file. Unfortunately, just because files are in a sublibrary doesn't make them part of the parent library. Similarly, there's no way to select multiple libraries at once for export. This means I have to export each sublibrary separately, then merge and de-duplicate the output files (since entries can occur in multiple libraries, and this will upset BibTex) to build my BibTex database. Very annoying! It would be nice if there were a way to export multiple libraries at once (or export all child libraries of a parent library) with de-duplication.
http://www.zotero.org/support/hidden_prefs
I believe that also applies to groups
edit: I hope that's what you want - your use of "collection" and "library" is a little confusing and seems to be the exact opposite of what they're actually called in Zotero, but I think I'm understanding this correctly.