I've built a simple project web site using a very handy tool called losango, that automatically creates the links for you project on sourceforge.net or codigolivre.org.br, which is a brazilian project similar with sourceforge.
This new release add a new functionality. By default, all users in the password database can be authenticated. Know you can supply an optional parameter containing the name of a group. All users will be checked if they belong or not to the group. If not, the authentication fails, and the password isn't checked.
The initial release for the OpenVPN Auth Passwd plugin is ready for download. The plugin was testes on some Linux distributions and OpenBSD, and it worked using both methods: shadow (shadow suite) and passwd (getpwnam).