Booking - Set max capacity

This example uses an accommodation that requires these booking rules:

• max capacity of 6 
• can be any combination of adults and children
• children over 11 are charged as an adult.
• children 11 and under are free.
• room price is set on 2 adult occupancy

Here's what I would do:

1. Set your capacity to 6 inside the Accommodation Type (Accommodation / Accommodation Type / Edit / Capacity / Adults = 6
2. Create a base price for your accommodation. Let's say $100 per night based on 2 person occupancy. (Accommodation / Rates)
3. Add a new service for extra guests over age 11and set the max to 4 per accommodation.  (Accommodation / Services) 
4. Combine adults and children as guests on checkout. (Accommodation / Settings / General / Guest Management / "Disable children option for my website (hide children field and use Guests label instead)"
5. Optional: Use the custom filter text below if you wish to add helpful text for the visitor. 

Optional custom text on checkout:

Here is a screenshotof what the custom text could look like on checkout page. This would print out just before the services / add ons list. This specific example has even more rules but you can adjust to your needs.

Here is the custom code in a public GIST. You will need to add this to your child theme functions.php file.

https://gist.github.com/ryanlabelle/340a1bf09d31e0a79bce8f43d29a2b58