I can't quite picture how this would look so I'm no doubt doing something wrong!

I have a list of businesses, they can each have many 'types' and many 'regions'. I would like to have a single gridfield overview of these and have the columns filterable.

I can add custom summary fields that will take the many types and show them as a comma separated list of names, that is all good, but filtering doesn't work on these columns.

I can't just put 'Types' in the summary field as I get an error fortemplate does not exist on ManyManyList

Filtering is really the action I want here and its a front end field so I don't have model admin's search on the left.

Any advice welcome!