I’ve hacked together a python3 script to do this, it’s very much a work in progress but you can find it here
You’ll need to tweak it a little for your set up (plexURL, Token and probably library ids)
My plan is to set up a cron job to run it every day, I might add a database to it so it can run multiple keyword searches but for now you could just run it for each keyword.
I’m using the EPG URLs and the movies one only returns a few of the actors, whereas the detail page for that airing contains a lot more, I may investigate that further.
Hope it’s of use to someone 
