Dear Steve,
are you using a view template to display the 'accommodations' custom fields group in the custom post type 'accommodations' page?
You can set this up in Views -> Settings -> View Template for Post Types and then choose the post type 'accommodation' and the template view you have customised with the custom fields group.
But this will only make the custom fields group display in all the post types 'accommodations'.
Overall I need to better understand what you want to achieve and what you've done so far, in order to try and help you solve the difficulties you're encountering.
Regards,
Ana