Probably the best way is to list each room individually, assuming there's no overlapping (shared) space. However I'm not convinced a boutique hotel is a right fit for Airbnb which generally focusses on low-cost home sharing.
That seems like the easiest way to do it.
Theres a tool to 'duplicate ' a listing. After listing one room and the main hotel part, duplicate this, change the room images and amend the description - keeping the shared content. Then, step and repeat.
I need some advice: I want to list our Cottage with during the winter months. On the Airbnb listing app, I have some choices of what type of property I have. Our property is a stand-alone, three-bedroom Cottage, with catering and housekeeping options available. It is part of River Birches Lodge, which is classified as Qualmark "Luxury Lodge." Any advantages in listing as "Boutique Hotel" over "House." If one goes with "House," what subcategory is best "Villa" or "Cottage." Anyone with experience with this let me know.