custom onerror for each code

$f3->set('ONERROR-403', function($f3){
 // -------------------------- error stuff here for "forbidden" ------------------------
 });
$f3->set('ONERROR-404', function($f3){
 // -------------------------- error stuff here for "page cannot be found" ------------------------
 });

its nasty.. but works ok in all my tests / project. reason for this... i want the default f3 behavior for errors except for 403 and maybe 404 later on