Show Device Groups on Map Widget

The Map Widget currently only displays map pins for devices (if I'm not mistaken).  We would like the option to show device GROUPS instead.  For example, given the device group structure shown in the attached image, we want to see ONLY pins for the devices groups Dubai and London.  Under each device group we might have devices or further device group hierarchies, the severity of the map pin should be that of the device group.  (I've tried adding the 'location' property to the device groups, but the map widget doesn't show a pins for the groups.)

We'd like to choose a starting group in the device tree, the map widget should then place a pin on the map for any child group with the 'location' property set.