"Consolidate" iPhoto library images already visible in Aperture

I have a bunch of iPhoto libraries that are already visible in Aperture but the files are stored inside the iPhoto library managed packages. I don't remember exactly what I did to make them visible in Aperture, but I'm preparing to move to Photos for OS X and I want a single managed Aperture library to migrate to Photos and iCloud Photo Library.

How can I simply "consolidate" the image files in the iPhoto libraries to be physically located inside the managed Aperture library? I just want to move the files that are already visible in Aperture, NOT re-import (and duplicate) them all.

I tried using "Consolidate" feature in Aperture, but that didn't seem to be available for these images.

Am I missing something?