There is no build in functionality supporting such a feature. However you could achieve your desired scenario via bindings.
First, you should bind the Visibility of every Expander to a dedicated property.
Second, in the property setter (or property change callback) you should trigger the synchronization logic and set other properties to collapsed when the current one is set to visible.
Hope this helps. Please let us know if you need more info or face any issues.
All the best,
the Telerik team