I'm designing a filter component for a listings site. Within the filter component, users are able to filter by area by selecting/ unselecting checkboxes - pretty straightforward. The items to be filtered are businesses that offer services (i.e. mechanic, laundry, plumber, etc).
My issue is that there is a good portion of businesses that don't have a physical location. This means they don't have a shop or service centre you can physically visit, rather you get in touch with them by phone or by visiting their website and they'll come to you.
How can I factor in this case in the filters without confusing users?
I'm afraid users will overlook businesses without locations even though they might be of great service to them - probably because people are used to filtering physical locations this concept might be obscure to them.
Any suggestions, advice, comments? Thanks.