Suppress "System Information" / "Access" Tab on Customer Form

Hi,

   I have a number of custom roles set up over a custom centre. I am trying to allow 1 of my custom roles seeing the "System Information" or "Access" tab on a custom Customer Form while preventing the other roles from accessing this. I would like both roles to use the same custom Customer Form.

    I don't believe there is a way to do this via Permissions at role level  (but if I've missed something then please feel free to let me know!).  So I am attempting to do this via a User Event (Customer beforeLoad) script. 

Using:-
form.getSubList('contactroles').setDisplayType('hidden');