Communities or Group Permissioning

Can you create communities or Groups to permission content as with dspace? I do not want one community/group to see the exhibits/collections/items of another group. Ideally I do not want to install multiple instances of Omeka to accomplish this.

We do not have communities or groups. If you want the archive and its exhibits to be completely separate then you will need multiple installations.

In the Fall, when we launch Beta, you will be able to more easily manage more than one installation. Through the interface, you can have different sites with different content, and it will be a little easier for you to manage.