Option to book services although the service duration overlaps with the break/opening times

We would love to be able to only take the opening times in account for the booking start of a service.
We are using the plugin for car rentals, and although we are only opened from 08:00 to 12:00 and from 14:00 to 18:00, we would like to offer our customers the ability to book for example a 4-hour-package at 12:00 and the return the car at 16:00.
As the customer only needs to drop off the car, is isn't required for us to be at the office while drop-off, only for pick-up.

More examples:

• if a customer books a 4 hour rental at 09:00 he should be able to return it at 13:00 although we are not open
• bookings starting outside our working hours should not be possible.
• a customer should be able to book a 24 hours rental anytime between our opening times