Yes, you can create a new branch for this user in the VPE. In the example below user John Smith gets special treatment.
After successful authentication, the username is checked with use of an Empty Action agent. In this example the variable session.saml.last.identity is checked. You could also use session.logon.last.username when using a Logon Page.
In the 'Set max session timeout to 5pm' event is a Variable Assign agent that sets the Maximum Session Timeout to 5pm.