Advanced selection

I have a folder with 2 different file tyoes (pdf, mobi)

Sometimes certain book/article comes with 2 diffrent extentions.
What I want to do is this:
If a certain book exists as pdf, I want to sekect and move the book with the .mobi extention.

Is that possible?

Easiest way would be to use the Duplicate File Finder in Filename (no extension) mode to find all the files that exist with more than one extension.

Then select *.mobi from the results and move them (assuming there aren't other non-pdf files with the same extensions).

A more complex way, that could ensure only the .pdf + .mobi combination is matched, would be to use scripting.