A resource group is a group that you can place resources in. The resource group makes it easier to see the resources together in the resource calendar, and is also used to link resources to events. When you create an event, you can choose not to assign a specific resource, but to have Duell automatically select an available resource from a given resource group. Note that all resources in a resource group will inherit the properties.
To create a new resource group, go to Booking > Settings > Resource Group.