The current version of the module only supports one appointment per time slot. You could, however, have one instance of the module for "Group A" and another for "Group B," so that they could each have one appointment during the same time slot. However, keeping track of resources (horses, people, etc) is not something that the module can do currently.
We are looking at integrating with a payment system for a future version of the module, but currently there is not any e-commerce integration.
We are alaways happy to discuss working with customers to fast-tracking features that they need. If you're interested in considering that option, you can send an email to sales@engagesoftware.com with reference to this post.
Hope it helps,