If you call Disney Dining and ask to speak to a Magical Gatherings representative, you can set up a Magical Grand Gatheings program.
Disney gives you a MGG #, that all the families in your group use when making reservations. When you make reservations just include the MGG number. When anyone in your group makes resrvations for the same restaurant at the same time, by using the MGG #, the reservation seating will be grouped together, automaticlly.
By doing this, you can make your agenda and distribute it to all the other families, then they can either join you or not, without you having to coordinate each and every dining activity.
Any special outings that require pre payment, like Hoop Dee Do; when you make the reservation, just give them a total count for the entire party and pay only for your own group, have the other groups call to pay, giving your reservation # and MGG #. They will be linked in and payment will be noted. Disney usually holds the reservation count for a week or two, allowing all the groups, included in your total reservation count to call and pay. After that time, they may cut the original reservation count back to the paid amount
This way, you can make the reservation, but not have to pay the whole tab, upfront, just your share.