Say it prominently in several places in each listing, making it clear that the cottages don't have a bathroom but that there are three nearby in the barn. This is an unusual arrangement and might not be popular. People generally want a private bathroom as close as possible to the bedroom. Is the barn close to the cottages? Is there a covered walkway, illuminated at night?
It would be a good idea to put together a plan showing the location of the cottages in relation to the barn and bathrooms. Include this prominently on your listings so potential customers have clear information on the set-up. Photos showing the locations are also essential.
Also make clear that the bathrooms are shared. You'll need to be on hand frequently throughout each day to check the cleanliness.
Personally, I wouldn't book a place like this. It would probably be acceptable to young people if priced reasonably.
