Let's say you already have a resource with a field for the number of guests.
For example, an hourly resource with a price of $100 / hour.
Now, create a pricing component for the extra charge for each guest over 8.
Enter a name for the component.
To create a formula insert a parameter for the field "number of guest" — F1.
We multiply $100 by the number of guests over eight.
And all this is multiplied by the number of reserved hours.
For that, insert another parameter for the number of hours — STEPS.
100 * ([F1] - 8) * [STEPS]
The formula will be negative if the number of guests is less than eight.
To avoid this, click on the Add condition button and set as a minimum number of guests to 9.
Now the pricing component will be applied only if the number of guests is 9 or more.
You will get the following configuration:
Choose 2 hours and 11 guests.
Formula: 100 * (11-8)*2 = $600.
Look at the example in action.