Disney calls this a Grand Gathering. You should call them.
I believe there are a couple of options. You can book everything yourself, or if there are multiple people paying for rooms, they can be booked individually and then linked.
Honestly, the folks in the call centers are VERY helpful (with occasional exceptions, but you can always hang up and call back to get someone else). You should call and explain what you’re doing and they give you very good advice.
P.S. You’ll find that for many people here, there’s no such thing as planning too far in advance.