Hello @TomUsingKNIME and welcome to the KNIME forum.
There are many post around the forum with this related topic challenge; we recently had the Weekly Challenge (Challenge 2: Split File and Save into Subfolders) ‘Just KNIME It!’ as well; where you can find many different user approaches to this problem. Mine one is a highly recommended one
https://hub.knime.com/search?tag=%23justknimeit-2
Some other related posts that could be useful
If you can’t get enough insights from it, you can provide some more details of your use case and we can help you to design a custom approach to it.
BR