Creating Collections and Subcollections

We would like to be able to create a few overarching collections (i.e. Native American) and then put several other collections under them as subcollections. For example, click on Native Americans and the Dakota, Ojibwe, Modern Life, Fur Trade, and Dakota conflict collections pop up for you to choose from. Is there a way to do this? My website is a resource database for teachers, so the more user-friendly it can be, the better. http://content.mnhs.org//education

At this time there are no nested relationships between collections or items. However, it's possible that this could be implemented with a plugin. If you're interested, join the developer google group (http://groups.google.com/group/omeka-dev) and we can help you through the process. It's also possible that others may be interested in collaborating on this.