Linking reservations so one person control fastpass & dinner reservations

[Cj2017]

I have been designated as the group planner for a trip to Disney world in December. There is about 15 of us going and need to know what is the best way for me to control all the Fast pass selections along with dinner reservations? Is it based on room reservations?

Thanks in advance!

*Additional info - One room is under my name and the others under my brothers name.