How do I get appointments+ to sync avaibility of user across entire network?

Appointments+ is a bit misleading. I thought it was going create a shared service providers database, and thus sync the service providers database, across all the sites in the network. This way if a user books a service provider on one site, that time slot shows up as unavailable on all sub sites in the network for that service provider. It seems to work individually on each sub site, which kinda kills the power of the multi site functionality.

Any ideas?