Batch convert iTunes Grouping tag to Label?

I've got a > 2000 track Rekordbox library, and I only just discovered the "Convert iTunes 'Grouping' to Rekordbox 'Label'" option.  I have a bunch of stuff with the correct grouping in iTunes.  I tried to select all my tracks and perform Reload Tags in Rekordbox but it did not update my label tags.  Is there a way to force Rekordbox to reload these?

Or is there a third party tool which can batch copy the Grouping tag to the Label tag in a way that Rekordbox will then read when I reload tags?

Thanks!