Is there any way to assign a default user, to bypass the captive portal, but then have access to to the captive portal if a user wishes to increase privileges?

Eg. At 11pm a policy stops access to the internet for the default rack, if a teacher wishes to have access after 11pm, they can go to untangle.domain.com/cpd and login through there to the teacher rack.

If anyone could help with this, or a variation of this, it would be greatly appreciated, as the majority of my users cry about the captive portal.

(Education Premium is installed)