Sort grouped search result by formula

[yuriiH (Yurii Halych)]

Hello.
I am trying to implement query which will sort results by the formula.

For example, we have the next entities:
{
"price":"1000",
"zip":"77777",
"field1":"1",
"field2":"5"
},
{
"price":"2222",
"zip":"77777",
"field1":"2",
"field2":"5"
},
{
"price":"1111",
"zip":"77777",
"field1":"1",
"field2":"5"
}

The first one I need to group result by field1 and field2 and then calculate the average price for each group.

Then I need to divide the price of each doc by average price value and sort documents based on this value.

Now, my query without sorting looks like:

    POST /entities/_search {
        "size": 0,
        "query": {
            "term": {
                "zip": {
                    "value": "77777"
                }
            }
        },
        "aggs": {
            "my composite": {
                "composite": {
                    "size": 500,
                    "sources": [{
                            "field1_term": {
                                "terms": {
                                    "field": "field1"
                                }
                            }
                        },
                        {
                            "field2_term": {
                                "terms": {
                                    "field": "field2"
                                }
                            }
                        }
                    ]
                },
                "aggs": {
                    "avg_price_per_group": {
                        "avg": {
                            "field": "price"
                        }
                    },
                    "results_per_group": {
                        "top_hits": {
                            "size": 100,
                            "_source": {
                                "include": ["entity_id", "price"]
                            }
                        }
                    }
                }
            }
        }
    }

Is it possible to do this somehow?