Bucket Aggregation with Distinct Source at multiple levels

[F_Doe_FW (Frederick Doe)]

Trying to see if I can pull out distinct values (keyword,float) on a bucket level.
Top Hits will give me a lot of values that I have to discard.

{
  "size": 0,
  "query": {
    "bool": {
      "filter": {
        "bool": {
          "must": [
            {
              "range": {
                "week_starting": {
                  "gt": "now-24M/d",
                  "lte": "now/d"
                }
              }
            },
            {
              "terms": {
                "compkey": [
                  "asdasd"
                ]
              }
            }
          ]
        }
      }
    }
  },
  "aggs": {
    "group_by_content": {
      "terms": {
        "field": "destination_city",
        "size": 10000
      },
      --> need to get all the unique values for a field in the aggregation above , do the same thing multiple times<--
      "aggs": {
        "group_by_content": {
          "terms": {
            "field": "origin_city",
            "size": 10000
          }
        }
      }
    }
  }
}

Hoping there is a way to get these via some pathing or sibling type aggregation.

Thanks for the read!