The below results in a group count of people by location name: g.V()hasLabel('people').out('people_location').groupCount().by('name')
I tried this to filter the list of locations by only those that begin with US: g.V()hasLabel('people').out('people_location').groupCount().by('name').matches("US*")
and g.V()hasLabel('people').out('people_location').matches("US*").groupCount().by('name')
but neither work.