Gary, lol, hahahahahahhahahaha. I tried it and it works. ON A SERIOUS NOTE,
I think what you're trying to to is by laying down two tracks shot from the same camera position except that the top track does not include the object you want to dissapear and the bottom track does. You than apply the cookie cutter to the first track so that the bottom track is showing through and than slowly move the cutout until the bottom track is no longer visible, thus making it look like the object you were exposing has dissapeared.
and then click on the links you find there, you'll get to a wonderful tutorial on how to use masks in V5 to let multiple "actors" (cats in this case) appear in the same scene, without a green screen. At the end of the tutorial, the author states:
"With any luck you'll while away hours creating duplicates of single actors exchanging soda cans in break rooms, composites of people jumping over cars, or semi-invisible characters taking out the trash."
Sounds like the thing you wanted to do.
The cat demo, while short, is very impressive and very instructive. You can download the project and all the media files directly from the tutorial site. Here is the direct link to the tutorial, if you don't want to first read the post above: