Deleting ARTIST if exists in ALBUMARTIST

Hi, What is the REGEX expression to delete the ARTIST entry (not the entire tag) where it also exists as an entry in ALBUMARTIST. The tag entries are separated by a semicolon.
This will be useful to correctly tag the soloist from the conductors from the orchestras and the composers as I see a lot of duplication from the MusicBrainz database. (I am not complaining about MusicBrainz, it has been spectacularly useful).

Thanks in advance.

Try an action of the type "Format value" for ALBUMARTIST
Format string: $replace(%albumartist%,%artist%,)

Super, although I need to apply the "Format value" to ARTIST for it to work as intended and it seems to only work for single entries, but it could just be me not concentrating clearly.