Process rule only when metadata file does not exist

This is most likely an edge case, but say I have thousands of images in raw format, some with metadata files structured like so:
I want to run a rule with multiple conditions, one being the *absence* of the .xmp metadata file. Is there a good way within the Hazel rule set to check this? Thanks for your help and for an awesome app!
- photo1.nef
photo1.xmp
photo2.nef
photo3.nef
photo3.xmp
I want to run a rule with multiple conditions, one being the *absence* of the .xmp metadata file. Is there a good way within the Hazel rule set to check this? Thanks for your help and for an awesome app!