Welcome aboard, Jenna! You must have a magical cruise with Disney in your future! And it sounds like you'll be traveling with a big group in four rooms! That makes the sailing even more fun!
If you are booking all four rooms and paying for them yourself, they'll be linked together in the reservation. Once it is time for
online check-in (75 days prior to sailing if you're a first time guest onboard Disney Cruise Line), you can do one of two things. First, you can choose to put the same credit card on each room for stateroom charges, or you could let the guests in the other staterooms use their own credit card as the card on file for onboard charges for that stateroom. It's up to you how to handle that.
The cost for each guest's
Port Adventure will be charged to the onboard account for the stateroom in which they are assigned.
I hope that helps as you begin to choose your adventures with Disney Cruise Line, Jenna. I'm happy to help with any further questions as you continue to plan your cruise!