(edit:) Basically, I want a wiki type area where registered users can edit page content.

I want to have an area where users can contribute. These should be sub-pages of my "Community" page. On that page I want to have directions and info about the Community area. This area should have 1) a navigation list of user-contributed sub-pages, 2) information about how to use this area, and 3) a link to create a new page. 1 and 2 are simple enough, but my questions are:

1) how do I enable users to add pages BELOW a certain page (when I set up the page for users to have editing privileges, they can edit that page as well as add pages below it, and I don't want them to be able to).

2) Is it possible to create a link that triggers the creation of a new page, or must I use the existing C5 chrome?