Beyond Pricing doesn’t have the facility for occupancy based (per person) pricing. The reason for this is that it may lead to discounting prices unnecessarily, rather than fulfilling the aim of Beyond Pricing to get the best possible price for each and every booking. 

However, you can if you wish, achieve the same effect. Determine your pricing in the Beyond Pricing dashboard based on your highest allowed occupancy, set your 'Default Pricing Capacity' in your SuperControl Property Settings to that highest number of allowed guests, and then set-up a 'Low Occupancy Discount' to reduce the prices by a fixed percentage if fewer guests are chosen.