On VB, I allowed members to Opt In to a specific user group so they could see additional content... I made it an action the user had to take to see the content.
In xF, I don't see how to do this. It appears that selecting to join a user group is not an option (that I can find), and Upgrading requires a value larger then zero, I don't want to charge for the upgrade.
Am I missing something easy? Is there an alternative way to allow a user to opt in to an user group?