How to merge identically structured, nested json files using jq

I need to merge an array in a series of identically structured, nested JSON files that share the same higher level keys.

The goal is to create a merged file while retaining all of the existing, higher level keys and values.

File 1:

{
  "account": "123456789012",
  "regions": [
    {
      "region": "one",
      "services": [
        {
          "groups": [
            {
              "GroupId": "123456",
              "GroupName": "foo"
            },
            {
              "GroupId": "234567",
              "GroupName": "bar"
            }
          ]
        }
      ]
    }
  ]
}

File 2:

{
  "account": "123456789012",
  "regions": [
    {
      "region": "one",
      "services": [
        {
          "group_policies": [
            {
              "GroupName": "foo",
              "PolicyNames": [
                "all_foo",
                "all_bar"                
              ]
            },
            {
              "GroupName": "bar",
              "PolicyNames": [
                "all_bar"
              ]
            }
          ]
        }
      ]
    }
  ]
}

Expected result:

{
  "account": "123456789012",
  "regions": [
    {
      "region": "one",
      "services": [
        {
          "groups": [
            {
              "GroupId": "123456",
              "GroupName": "foo"
            },
            {
              "GroupId": "234567",
              "GroupName": "bar"
            }
          ]
        },
        {
          "group_policies": [
           {
              "GroupName": "foo",
              "PolicyNames": [
                "all_foo",
                "all_bar"                
              ]
            },
            {
              "GroupName": "bar",
              "PolicyNames": [
                "all_bar"
              ]
            }
           ]
        }
      ]
    }
  ]
}

I have tried the following based on answers to other questions of this type with no success:

jq -s '.[0] * .[1]' test1.json test2.json

jq -s add test1.json test2.json

jq -n '[inputs[]]' test{1,2}.json

The following successfully merges the array but lacks the higher level keys and values in the results.

jq -s '.[0].regions[0].services[0] * .[1].regions[0].services[0]' test1.json test2.json

I am assuming there is a simple jq solution to this that is escaping my searches. If not, any combination of jq and bash will work for a solution.