PmWiki has the capability of classifying pages into groups of related pages. WikiWords form 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.
By default, the RecentChanges page of each group shows only the pages that have changed within that group; the Main.AllRecentChanges page shows all pages that have changed in all groups.
Creating a new group is as easy as CreatingNewPages; simply edit an existing page to include a link to a page in the new group, then click on the '?' to edit the page.
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).