Hidng Site Tree Pages and Tabs by adding an Editor Content View of the CMS

Obstacle:
Limiting accessibility and viewable content by user permissions.
I wish to limit what a user has access to and/or what they can see in the SS CMS, specifically the site content tree. Currently "limited permissions" operate by graying out pages, but allow viewing.

Solution Needed:
Expanded permissions through modification to current build that would hide pages in the Site Map Tree.

Suggested Customization: When a user logs in with EDITOR PERMISSIONS they would see a different “stripped-down” version of the CMS, removing the irrelevant site map tree areas and top nav elements.
(i have this illustrated in a pdf)

In the interest in saving time & expense, i am seeking programmers with proficiency in SilverStripe specifically.


CLARIFICATION:

In Admin view, both the TOP level pages and SUBpages need permissions independent of one another.

In other words, a top level page may not give an editor access permissions, but one subpage of that level may grant editor permissions.

Therefore, setting should be:

- who can edit this page? (as illustrated in the diagram, for every page, top and sub)

- copy these settings to all subpages in this group? (when checked, permissions of a top level page are copied to all sub pages, but sub pages can be subsequently manually changed on a per-page basis.