merging endnote library's

what i want to do take two copys of my endnote icon and data folder send two people away with a copy and have them add different references the their copy then when they come back merge the two copy’s to one so that i then have all the data in one

 is this possible

Yes, you can always import one library into the other, making sure to select discard duplicates.  First run duplicate search on each library to ensure they don’t have any duplicates to start with, though.  It would probably be easier, to ask them to just create a new library with additional references and import those.  What this will not do, is “update” any references to which they make changes.  That is much more difficult. 

But can it be done? And how?

So rather than importing with discard duplicates (which would do the exact opposite, and throw away the updated record), you could try this - but it isn’t exactly automated, —

Since there is an “last updated” field now, I would display that in my library display view,  sort on that on the edited version of the library, drag and drop the appropriate records from a “since” date,  into the “permanant” library.  Then (with X3, I wouldn’t do this with X2) run the find duplicates and keep the most recent, presumably updated copy.  This would get new records and newly updated records would be the copy you retain.