Smarty... Directory Structure?

I'm using smarty on a site with the following directory structure:

/app/public_html/
/app/public_html/admin/
/app/public_html/superuser/
/app/smarty/templates/
/app/smarty/templates/admin/
/app/smarty/templates/superuser/

Obviously, there are other directories (for Smarty, and others) but I have left these out for simplicity.

The different directories represent different levels of authorisation.


I want to use a standard basic template for each level of authorisation. Normally Smarty picks up the template from the template directory that relates to the current directory eg.
/app/public_html/superuser/
/app/smarty/templates/superuser/


How do I go about storing a single template?? (I know I can use absolute paths, but surely there is another way?)


Cheers,

Ben