You will need to create the same number of homes as there are Airbnb listings, and associate each home to each individual Airbnb listing. Following which, associate the lock to all the home listings.
For example, if you have 5 Airbnb listings, you will need to create 5 homes from the Manage Homes menu. Associate each home to each Airbnb listing. Go to the lock settings page under Lock Info to select the home associations, and your lock will be able to generate and send PINs for all listings from that lock.