Is it possible to add custom security groups (creating mini sub-communities)

[awesomerobot (Kris)]

Yes, you can create categories that are only accessible to specific groups of users. This guide should help:

Understanding groups and category permissions (security settings)

See this video tutorial for an example of how to use these features: Create a private category with limited access for a certain group The Security tab on the category edit page is used to control both the visibility of categories and what users can do in a category. This is done by defining an access list of groups that associate a group name with an access level. The default permission for a new category is that the group everyone can Create/Reply/See. This means that a…