"aggs": {
            "groups": {

                "terms": {
                    "field": "comments.name",
                    "order": {
                        "rate": "desc"
                    }
                },

                "aggs": {

                    "rate": {
                        "min": {
                            "field": "comments.age"
                        }
                    }
                }
            }
        }
    }
}