I have two sources - a watched folder, and a Lightroom Classic catalogue.

The LrC catalogue images, apart from a relatively small number, are all in the folder structure that is included in the Watched folder source, but not all of the images are imported into Lightroom. 

Basically, I ingest from the cards into a folder:

Then I make my selects and move them into a sibling folder:

Then I import the images in the _selects folder into Lightroom Classic for editing, and then export them into a subfolder under _selects/_exported.

In Peakto, I can either show all the images in the Lightroom source, all the images in the Watched Folder source, or all of them together - but I can't figure out how to only show images that are in the Watched Folder source that DO NOT appear in the Lightroom source as well.

Basically, I need to go through all the images I didn't import and double check which ones are ok to permanently trash, or which I should keep for potential editing in future...

How do I do that - is it currently possible, and if not, could you consider implementing a way of filtering images that are in one source but not the other?

Thanks!