How to work with virtual (seo) URLs?

Hi folks, my another question is how to work with URLs like below in PHP: http://www.example.com/section/ http://www.example.com/section/subsection/ http://www.example.com/section/subsection/subsubsection/ http://www.example.com/section/subsection/subsubsection/ .... These URLs works very well with this mod_rewrite rules: ---- RewriteEngine On #check if file or directory real exists: RewriteCond %{REQUEST_FILENAME} !-f RewriteCond %{REQUEST_FILENAME} !-d #do the rule only if the address has no extension: RewriteCond %{REQUEST_URI} !\.[[:alnum:]]+$ #replace /whatever to /whatever/, not apply to whatever/! RewriteRule ^(.+[^/])$ /$1/ [R] #do the rule only if the address ends with trailing slash: RewriteCond %{REQUEST_URI} ^.*/$ #if the rule ends with trailing slash then redirect to index.php.. RewriteRule ^(.*)/$ /index.php?p=$1 [L] ---- So Apache stage is solved, but how about the PHP stage? The problem is that there can be many of subsections and how I can know that for example /animals/ is a subsection of /photogallery/ and not /profile/ ??? [url]http://www.example.com/photogallery/animals/[/url] - GOOD [url]http://www.example.com/profile/animals/[/url] - BAD How do you solve these things? One idea which I had is to store sections in array an then compare them with the section's name in URL, but I can't get it work for more nested URL's. Any ideas or web resources are appreciated! Cheers.