How to integrate Appointments+ with Marketpress from separate sites?

Hello WPMUDEV!

I’m using appointments+ and I need to have individual sites set up for each service provider because they will need to be in their respective time zones and I would eventually like to include blogging and membership functionality that would be separate for each site. So this would essentially be many sites but appear to the user to be part of one main website. I would like to figure out how they can have their own appointments and digital products on their site BUT have the customer only have to check out once through the main site. Will all of the products from the different sites go into the shopping cart in the main site if I just chose the “global shopping cart option”? Chained payments are not an option unfortunately, we need to have all of the money come through us. Thanks so much for your help!