Using min_score in a bucket selector pipeline aggregation

[crickes (Steve Crickett)]

I have an aggregation which produces an output like this using a significant terms aggregation:

{
  "took": 88,
  "timed_out": false,
  "num_reduce_phases": 3,
  "_shards": {
    "total": 1430,
    "successful": 1430,
    "failed": 0
  },
  "hits": {
    "total": 1071145,
    "max_score": 0,
    "hits": []
  },
  "aggregations": {
    "cluster": {
      "doc_count_error_upper_bound": 0,
      "sum_other_doc_count": 0,
      "buckets": [
        {
          "key": "group_1",
          "doc_count": 223759,
          "significant_methstat": {
            "doc_count": 223759,
            "bg_count": 1054597843,
            "buckets": [
              {
                "key": "type-1",
                "doc_count": 51683,
                "score": 0.08758472205101155,
                "bg_count": 176615496
              }
            ]
          }
        },
        {
          "key": "group-2",
          "doc_count": 189927,
          "significant_methstat": {
            "doc_count": 189927,
            "bg_count": 1054597843,
            "buckets": [
              {
                "key": "type-2",
                "doc_count": 49170,
                "score": 0.14131842028473424,
                "bg_count": 176615496
              }
            ]
          }
        },
        {
          "key": "group-3",
          "doc_count": 104259,
          "significant_methstat": {
            "doc_count": 104259,
            "bg_count": 1054597843,
            "buckets": [
              {
                "key": "type-3",
                "doc_count": 41541,
                "score": 0.1317421370332497,
                "bg_count": 315782621
              }
            ]
          }
        }...

I would like to be able to use the bucket selector aggregation to effectively drop buckets where the score is less than 1. You can do something similar with doc_count, but I can't figure out what syntax I should use to reference the score value of the bucket.

Is it even possible to reference the 'score' of the bucket in a significant terms aggregation?

Thanks in advance.