For any future session you setup in WrestlingIQ, a new smart message group will be setup so you as a coach or admin can easily message everyone registered for that session.
After you create a session, you will see the group in the messages section of WrestlingIQ. That group will automatically add parents (and wrestlers) to the group when a parent successfully registers them for that particular session.
You can still create any number of groups or direct messages, but hopefully this feature will save you a little time when you want to send a message to only parents registered for a particular session.