Run a custom error page in the same sub directory as the htacess

Hi, I know that htaccess modrewrite is based on document root. Here is my path to my custom error files example.com/subdir has its own htaccess and its own 403.shtml file (i have the 404 taken care of with some fancy modrewrite so i dont need the 404) But i need the 403, at first i thought i could use the htaccess