create shared folder for all (sub-) domains

[cware]

Hi there... this is my first posting in this forum...

I'm currently working on a service that allows others to register subdomains...
on http the site shall be displayed and on https there shall be the configuration interface for the user...
the thing now is that for all subdomains (propably > 100 somewhen) the source code of the configuration interface is exactly the same...
so my idea was to have a single code base that is located somewhere like /srv/www/vhosts/example.com/shared

but how do it get that to work so that alle subdomains get their open_basedir property set automatically? I don't want to have to the property for every subdomain...
additionally it would be great if other vhosts/domains would also inherit this feature of a shared folder...


cheers...