Go onto Royal Caribbean's website and log-in. Under your "Upcoming Cruises" section, at the top right corner underneath your name, C&A #, and Status, you'll see "Add Another Cruise". Click on that link, fill in the info, and it will automatically link your cruise reservations together. Sometimes it acts up and says it's "working on it" for a very, very long time. If you refresh the page and go back to your cruise planner, the reservations should be linked. You'll need the last name, birthdate, & reservation number of someone in each cabin to do so. They only let you link a maximum of 6 reservations together on the same sailing by doing it this way.