How to change all external links to "nofollow" but only by user role

I am looking for this question How can I nofollow all external links by user role? I have found these codes to convert all links to Nofallow, can anyone change these codes according to the user's role https://www.codespeedy.com/relnofollow-for-all-external-links-in-wordpress-using-code/

// add nofollow to links
function nofollow_for_external($content) {
    $content = preg_replace_callback( '/a[^]*href=[|\']([^|\']*)[|\'][^]*([^]*)\/a/i', function($m) {
     if (strpos($m[1], domain.com) === false)
          return 'a href='.$m[1].' rel=nofollow'.$m[2].'/a';
     else
         return 'a href='.$m[1].''.$m[2].'/a';
     },
     $content );
     return $content;
 }
 add_filter('the_content', 'nofollow_for_external');
// Stop self pingback
function disable_self_ping( $links ) {
    $home = get_option( 'home' );
    foreach ( $links as $l = $link )
        if ( 0 === strpos( $link, $home ) )
            unset($links[$l]);
}
add_action( 'pre_ping', 'disable_self_ping' );