Batch upload names with multiple Vouchers to a checklist

[Barkworth]

I have downloaded the list of names not in a checklist I am creating. Some of the names are supported by multiple specimens. I am hoping someone knows (or would be intrigued enough to write) is an Excel expression for concatenating the catalog numbers of records vouchering the same taxon. Write now, I use =concat(B16,", ",B17,", ",B18)
AJK Missing.xlsx
adding the cell numbers by hand - then copying and pasting as value the results of the expression into the "source" field of the first record for a given name Using the link function in Symbiota is also time consuming. This seemed like a good approach but ...