PmWiki has the capability of classifying pages into groups of related pages. WikiWords act as links between pages of the same group; to create a link to a wiki page in another group, you use
[[GroupName/WikiWord]] to create the link.
To list all the groups in a site, try the markup
Each group can also have GroupHeader or GroupFooter pages that contain text to be automatically prepended or appended to every page in the group. A group can also have a GroupAttributes page that defines attributes (read and edit passwords) shared by all pages within the group. Each page can also have its own individual read/edit password that overrides the group passwords (see PmWiki.Passwords).