Thank you for your message.
The only possibility is to split the 40 people either in 2 groups of 20 people each or you can arrange them in groups of 30. This is the only possibility.
For your tree busses with 40 people each, we have only the following times left available on October 5th: 12:30, 15:00 and 18:15.
Please let me know if you wish to book the tour as such.