[Koha] Marc imports

[Frances Leahy]

Hi,

I'm hoping that somebody in the community might be able to help me with the following problem.

We want to be able to download a batch of marc from one of our current suppliers, to replace 4000 Dawsonera e-book records (who have now gone into administration).  This would ordinarily be easy enough to do, as we would just import the new records and they would match the old records via isbn.  However, we have other e-books on Koha which we have purchased from other suppliers with the same isbns, and we wouldn't want to overwrite these, so was wondering how this could be done if at all?

I wondered if there was a way we could maybe add some component of the url from the old Dawsonera records into the matching process, so that it was only these records that would become overwritten?
If anybody knows how to do this or has any ideas, it would be much appreciated.

Hoping that somebody out there knows how to resolve this.

Best wishes
Frances