Segment Site with Access Control, Restrict Edit & View

I have been digging around for some User Permissions Module that I would like to use for the site. With our site we would like to segragate into three different groups that not only have Editable access pertaining to only their sections of the site, but also have viewable permissions restricted as well. For instance:

Group - A
Group - B
Group - C

Group A needs view + Edit permission to section A, B, & C - can basically view and edit all portions of the site.
Group B needs view + Editi Permissions to section A & B - Restrict View + Edit for Sections C
Group C Needs view + Edit permissions to Sections C - Restrict view + Edit for Sections A & B

I am using Drupal as a developer network for our employees. We also use contractors that require access to the site but not proprietary information, and we also have general Users (not unregistered anonamous users), That have access to general information but are restricted to contractor & Developer sections.

I found this Tutorial on Taxonomy Access Control (http://drupal.org/node/153686/) , but it does Mention Edit specifically. Am I missing something or does this not include Permission Grating for View rights to certain sections as well?

Also, I notice when I test content creation for pages, stories and so on that Drupal uses a standard new page(node) naming convention, ie) node/###. I wanted to name some sections such as node/devbox and create pages that link to that particular section, Sort of Like Mediawiki. Is there a way to do this or are there security risks in doing so? Understandably Drupal is not a wiki. Some insight on this would be helpful. Thanks in advance for all your help!