With HelpDirs we can specify which of the subdirectories will be internal nodes of the help tree. Moreover, we can specify labels for the nodes and a link to load when a particular node is clicked. The link is relative the node. For instance:
HelpDirs {html-version "GiD Help" "intro/intro.html"} \ {html-customization "GiD Customization"} \ {html-faq "Frequently Asked Questions"} \ {html-tutorials "GiD Tutorials" "tutorials_toc.html"} \ {html_whatsnew "What's New"}