Using this sample data consisting of 3 separate documents in the same container:

{
  "id" : "doc1",
  "manager" : "John",
  "country": "Germany"
}

{
  "id" : "doc2",
  "manager" : "John",
  "country": "Netherlands"
}

{
  "id" : "doc3",
  "manager" : "Jack",
  "country": "Austria"
}

I would like to write a query that returns a list of objects containing the distinct manager names and the countries they're responsible for. Something in the shape of:

[
{
  "manager": "John",
  "countries": ["Germany", "Netherlands"]
},
{
  "manager": "Jack",
  "countries": ["Austria"]
}
]

I have tried (and failed) with joins, subqueries, and JSON object projections.