CoNotification GroupMember Find Parameters

in CoNotification::register()

// A clever contain will perform our join, but nest our data
$args = array();
$args['conditions']['RecipientCoGroup.id'] = $recipientId;
$args['contain']['CoGroupMember']['CoPerson'] = 'EmailAddress';
// doesn't this need to check for member vs owner?
// and probably that the group is active?