From Joomla! Authentication Tools (JAuthTools)

JACLPlus is a popular ACL solution for Joomla!. JACLPlus allows the ability to create extra groups on top of the existing Joomla! groups. These groups can be auto assigned and synchronized using JAuthTools with the group map functionality in the exact same way as the built in groups. Additionally there appears to be no issues with SSI or SSO.

[edit] Testing