add_filter('wp_mail','redirect_mails', 10,1);
function redirect_mails($args){
    $to = $args['to'];
    //$args['subject']
    //$args['message']
    //$args['headers']
    //$args['attachments']
    $user = get_user_by( 'email', $to);
    $_role = get_user_meta($user->ID, 'my_custom_role', true);
    if ($role == 'opportunity-owner') {
      $test_mentor_email = get_option('test_mentor_email');
      if ($test_mentor_email != '') {
        $to = $test_mentor_email;
      }
    }
    $args['to']=$to;
    return $args;
  }