Currently the merging process let's you select which fields ought to be copied over to the "winning" record from the "loosing" record(s). Afterwards, the "loosing" record is deleted (moved to tables "deletedbiblio" etc.). One problem with the current solution: You can't tell after the fact, which deleted record was merged with which existing record. This is bad if you want to provide stable links to bibliographic records, for citation in research papers for example: Ideally you would want to be able to redirect to the "winning" records if somebody calls URL to a deleted record.
One solution: 1. Add a toggle when merging "keep merged record" 2. If the toggle is active, let the user specify into which of the loosing record's fields to write the replacement's system number. 3. Remove all data from the loosing record except the replacement's sys number If somebody navigates to a record replaced in this manner either redirect directly (OPAC) or show a link to the replacement record (Backend).
http://www.loc.gov/marc/bibliographic/bd882.html