A+ multiple providers with multiple dummy providers?

Hi everyone,

We have recently set up a website for a client who has two physical products that are hired out :-
- A large cart hired for a day at a time and;
- A small cart hired out for 4 hours at a time

To make this work, we created a dummy provider for the small cart so that both carts can be hired at the same time (to the same or different persons) since our client just drops the cart off at the required location and collects it at the end of the hire period again.
http://misslollyscandycart.com.au/make-an-appointment/
(Please note this is a live site. DO NOT make test bookings)

We now have the request to add franchisees to the website. In essence, each franchisee will offer the same services and need to be able to take bookings in the same way. Each franchisee will have a large and small cart to drop off at and collect from each booking under their area.

Does anyone have any ideas on how to achieve this? All I could think of was doing it as a multisite with each franchisee effectively having their own A+ configuration but it seems overkill?