Renaming files in date sync

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Say I have 2 same cameras with dates exactly sync'd. I take photos and put them in 2 folders.
I want to rename the files in date order event_####. But after the rename I want to separate them back to 2 folders as they were taken by 2 people.

How can this be done? Currently I see no way of doing it, and you can't add exif columns to the file list otherwise I'd go by copywrite line.