This page explains how to link bookings
You can link two or more bookings. One booking becomes the master booking which the other booking/s link to. Go to BOOKINGS:
1. Decide which booking is the "master booking"
2. Open the booking you want to link, go to the tab "Invoice" and enter the booking id of the master ID in the field "Link to Booking ". SAVE.
Linking bookings does not change the invoices. Each booking will keep their own invoice. If you want to combine them you will need to do this manually.