Set Attr Meta - Copy keyword value from another keyword?

On occasion I buy a CD that is a compilation of several Artists.
A good example is a movie soundtrack.
After I convert the tracks to mp3 for my mp3 player the Artists field has the name of the Artist of that particular track. This is all fine except that my mp3 player creates a virtual folder structure that uses Artists metadata rather than the name of the folder that contains the tracks. The result is that I end up with virtual folders of every Artist on the CD.

The simple solution is to copy Artists metadata to Album Artist and then give Artists the value Movie Soundtrack or something similar. I have been able to do this with an old and out of date program called Tag and Rename, but I wish I could do this in Directory Opus.

Is there a way to do this, perhaps calling Evaluator for part of it ?
Or is it easier and I don't see it yet?

Some of the date/time fields support copying from similar fields. For things like Artist/AlbumArtist, you'd probably need to use scripting.

Some examples here (although I'd add some error checking in case the tag doesn't exist): How to copy mp3artist name into mp3albumartist

Thanks much !
That worked !
My next thought was to append the filename and then try to set the value from that.