This assumes you have PHP/FastCGI Example set up.

Example (partial) configuration:

server { 
     listen       80;
     server_name  example.com;
     root         /sites/example.com;
     
     location / {
       index index.php;
     }
     location ~ .*\.php5?$ {
       include       fastcgi.conf;
       fastcgi_index index.php;
       if ( $uri !~ "^/images/" ) {
         fastcgi_pass  127.0.1.1:1026;
       }
     }
     location /wiki {
       include        fastcgi.conf;
       fastcgi_param  SCRIPT_FILENAME    $document_root/index.php;
       fastcgi_param  SCRIPT_NAME        /index.php;
       fastcgi_param  PATH_INFO          $fastcgi_script_name;
       fastcgi_pass   127.0.1.1:1026;
     }

}