apache - If No File, Rewrite URL -

I have two .htaccess files that I need to combine in one.

The first one does a simple file extension remover

In order to keep the second URL, it rewrites all the requests to go to the third party's app.

What do I need, the rules are not enough to be smart, to see on other servers if the file is present at first

Rule1:.!

  RewriteCond% {REQUEST_FILENAME} at RewriteEngine -dRewriteCond% {REQUEST_FILENAME} \ php -f RewriteRule ^ (*.) $ $ 1.php  

Rule 2: (. *)

  Option + FollowSymLinks + Index RewriteRule RewriteEngine Current ^ $ http://third.party.com/$1 [P] #RewriteCond% {THE_REQUEST} ([^ ? \]) #RewriteRule ^. * $ Index.php /% 1  

I am away from an .htaccess wizard, so I have all the ears for suggestions.

You can add the L flag to stop typing on a given rule. for example:.

  RewriteCond% {REQUEST_FILENAME} on RewriteEngine -dRewriteCond% {REQUEST_FILENAME} \ -f php RewriteRule ^ $ $ 1.php [L] RewriteRule ^ ((*.). *) $ Http : //third.party.com/$1 [P] #RewriteCond% {THE_REQUEST} ([^? \]) #RewriteRule ^. * $ Index.php /% 1  

(see "Stop the rewrite process").