Collapse/Group search query result by a field with supporting sort options

I have some documents like the following examples:

{"id": 1, "digest": "A", "date": "2020-05-07"}
{"id": 2, "digest": "A", "date": "2020-01-07"}
{"id": 3, "digest": "A", "date": "2020-03-07"}
{"id": 4, "digest": "B", "date": "2020-01-02"}
{"id": 5, "digest": "B", "date": "2020-01-01"}
{"id": 6, "digest": "C", "date": "2020-01-05"}

and I want to group the result of the search query by a field (like digest in this example) in the way that:

• the result items sort by date descending
• the group leader must be the record which has the minimum date (for example id=2 between 1,2,3 which have the same digest)

in summary, the result that I expected is something like:

[
   {
      "id": 2
      "inner": [{"id": 1}, {"id": 3}],
      "date": "2020-01-07"
   },
   {
      "id": 6
      "inner": [{"id": 6}],
      "date": "2020-01-05"
   },
   {
      "id": 5
      "inner": [{"id": 4}],
      "date": "2020-01-01"
   }
]

I have tried collapsing fields but by this way, I can't select group leader item and because digest is a hash value, not a static tags, I can't find aggregation method for that.