[fw-mvc] Controlled access in a form how to

Hi,

I have roles like...
guest->member->manager->admin

A member can create/edit her own articles (this is checked in the controller; if the user_id of the article matches the member's id). I am not sure if this is the right/best way/place to do this :)
The "manager" and "admin" can edit articles owned by any "member"

Now the issue
============
The form used for creating and editing articles has a display group "Administration" which should not be viewable/accessible to the "member" but can be viewed/accessed by "manager" and "admin", also...
the "administration" display group has two form inputs (e.g. A and B) of which B should not be viewable/accessible to the "manager".

How can the above be achieved?
All solution/guidance is appreciated.

best,
-R

P.S. The project is a standard Zend MVC application. If you need further information to provide assistance, please feel free to ask.