Two edit controls on the same page with different image path

In my multisite CMS I am successfully using session variables to pass the image directory to the upload connector. I now have a situation where I'd like to be able to specify 2 different image locations on the same page. One is a standard description with "normal" images. The other is a special category for which images are stored in a different directory. It can't logically be done using the session alone because the script has finished running before any image lookup is attempted so both objects will see exactly the same session variables. Is there an identifier passed in the url to the connector (php) that I can use to differentiate between instances? If there is I can build that knowledge into my session variables and the connector can access the variable set for its use.