Conditional APM Session Creation

Hello, I'm fairly new to the APM module and have been experiencing a problem while attempting to create a per session policy. We have a single VS which was planned to host multiple URLs which some will require SAML auth and others will not due to the end user not having an account. The problem I'm running into is that sessions are being created for users without accounts. Once they do have accounts and attempt to navigate to a SAML auth required URL they already have a session so they never are prompted to sign in and the page errors out since the pages require SAML attributes. Is there a way to create a session conditionally based on a URI? I have tried an iRule to bypass the per session policy for certain URIs which works but the auth breaks. The only thing I can think of is a separate VS for the user portal and associated URIs. Has anyone run into a similar situation or have any thoughts on a possible solution?