It's not ME between the airport and the cruise port - it'd be cruise transfers, most likely provided by Mears.
Best bet, probably, would be rent a car at the airport, drop off your luggage and co-travelers at the port, and return the car to whichever agency; they will then shuttle you back to the ship. When you get back, reverse it - get a shuttle to the car rental place, pick up the car then your traveling companions, drive to the hotel, and return the car in that area.