How do you handle a directory with both brick/mortar AND mobile businesses?

I’ve gone around and around with this. I would like to hear how others deal with this…

I have a local directory that has both local businesses that actually have physical locations AND local businesses that are mobile and do not have physical locations but have a range that they will work…say a county or a list of cities… All are listed in my directory and I’m finding it difficult to figure out how to deal with the mobile businesses because my instructions to just put “mobile business” in the address field and pick a city and set on the map aren’t really sufficient.

I was telling them to choose the county on the drop-down but that’s not working. It keeps defaulting back to a city and inserting a random address and they have to re-write the mobile business line again. Plus many of these businesses work out of multiple, adjacent counties. And my directory is for an area that has multiple counties, so sticking with just one county on the map doesn’t really work either.

I don’t like the idea that they will have to list themselves multiple times, one for each area they work out of because that will mean in the random listings pages they are going to potentially get shown multiple times in the same screen. Messy. It seems like there should be a better solution to this. Is there?