Captive Portal Type: Email Collection question

Hi,

I'm a newbie here. I was wondering, is there a setting/s for setting the duration of a user logged-in via fortigate captive portal with Email Collection as the captive portal type to lets say an hour then the logged-in user will be logged out when the 1 hour is up?

This is doable if captive portal type is set to authentication or authentication + disclaimer and I was wondering if its also possible with email collection (captive portal type) or was it not possible?

Any help or advice would be greatly appreciated. I'm using FortiOS 5.4. Thanks in advance.