You could ingest all the raws at the end of the day, and upon your PM preferences (IPTC/XMP read first from JPEG), you could pair them with the tagged jpegs, deleting the rest. That's what I do if I am shooting raw+jpeg and filing the (in-camera tagged) jpegs directly from camera through wifi, when I want to revisit the raw files later. I normally have PM set to read metadata from raws first, because that makes more sense to me, but it's easy to change once in a while.
Also, if you have a set of jpegs in PM, you could do a Save selection to a text file (which saves a list of the selected filenames), edit the text file with any text editor doing a find and replace (changing .jpg to .cr2 or whatever), browsing your card in PM, and do a Load selection with the edited text file - that will select just the corresponding raws, and you could copy them to disk.