How to merge duplicate records in a library

I recently became the administrator for my organization’s EndNote library with one of the first tasks being cleaning duplicate records. The duplicate records are spread throughout multiple groups and cited in multiple documents. I do not have a history of which duplicate record was used in which document(s).

Rather than deleting one or more of the duplicates, how do I merge/combine the duplicates so that it retains group location and the

Note: using PC desktop version, EndNote X8

I don’t know your area or source of the library records, but if they are mostly from Pubmed, I suggest using the accession number rather than record number in the temporary citation and then it won’t matter which one you keep.   – This is done in each persons desktop library preference settings.