A way of doing this would be to override the user’s role when they sign up. BuddyPress provides a hook we can use for this bp_core_signup_user. So, you could do something like this:

function fuzzllc_set_default_role( $user_id ) {
$user = new WP_User( $user_id );
$user->set_role( 'keymaster' ); // keymaster can be whatever you…[Read more]