OK, I'm not sure of the syntax. I see the trigger:
$_PLUGINS->trigger( 'onAfterUserRegistration', [ &$newUser, &$newUser, true ] );
Do I need a new CB field, cb_gj_id, to store the group id in so I can do
$newUser->set( 'cb_gj_id', $cbgroup );
Then in the AutoAction, how do I access that? [var1_cb_gj_id]?