At some point (number of people) you may be better off using a private service to get between the Cancun airport and Playa del Carmen (ferry area). Two suggestions for a start
USA Transfers
Cancun Transfers, Riviera Maya Transfers, Cancun Tours, Riviera Maya Tours and Special Packages at Comfort Travel Cancun, call us 011-52-998-2535837
USA Transfers
Cancun Transfers, Riviera Maya Transfers, Cancun Tours, Riviera Maya Tours and Special Packages at Comfort Travel Cancun, call us 011-52-998-2535837