Custom Field in Post-Type Slug

Ok so i have a website i'm working on, all is very much fine with every aspect, except with the slug for one post type i've created.

Basically i have 4 post types.

These are perfect as they are:-
Network
http://www.website.com/network/network_name

Shows
http://www.website.com/shows/show_name

People
http://www.website.com/people/person_name

The problem comes with the 4th one "Episode"

Rather than it being the default:-
http://www.website.com/episode/episode_name

I need it to be:-
http://www.website.com/show/show_name/episode/episode_name

I have set up a custom field for the user to select a show, so that's all taken care of but putting this into the slug is a whole different story. Any help on this would be greatly appreciated

I've searched all over the internet but to no avail and most posts are severely outdated.

Thank you