The tree below demonstrates the following features:

• Only one base layer is selectable (Others will be unchecked automatically). You can see this behavior when selecting base layers in the "Base Layers" group.
• Nodes can be mapped to several layers, and separate nodes can control the same layers. In the "Overlays" group below, you can see that checking the "Parkings and Summits" layer will check both the "Parkings" and "Summits" layers automatically.