Data.js

{
  "AccountId" : new BinData(3, "HUS1wBo9bUG33nsC/OLBTQ=="),
  "AdministratorId" : new BinData(3, "AAAAAAAAAAAAAAAAAAAAAA=="),
  "GroupMembers" : [{
    "GroupId" : new BinData(3, "AAKaDg9ChUClP6Le3bf7Mw=="),
    "GroupMemberId" : new BinData(3, "AAKaDg9ChUClP6Le3bf7Mw=="),
    "Phone" : {
      "Valid" : true,
      "Number" : "+46000000000",
      "Country" : {
        "Name" : "Sweden",
        "Prefix" : "+46",
        "IsoCode" : "SE"
      }
    }
  }, {
    "GroupId" : new BinData(3, "HUS1wBo9bUG33nsC/OLBTQ=="),
    "GroupMemberId" : new BinData(3, "HUS1wBo9bUG33nsC/OLBTQ==")
  }],
  "PhoneNumber" : {
    "Valid" : true,
    "Number" : "+46000000000",
    "Country" : {
      "Name" : "Sweden",
      "Prefix" : "+46",
      "IsoCode" : "SE"
    }
  },
  "UnitId" : new BinData(3, "AAKaDg9ChUClP6Le3bf7Mw=="),
  "_id" : ObjectId("5253f6dd89f6fc8a1c70fd72")
}

Fields.js

{
  "GroupMembers.$": 1
}

Find.js

{
  "GroupMembers":
	{
		$elemMatch:
		{
			"GroupId": new BinData(3, "AAKaDg9ChUClP6Le3bf7Mw==")
		}
	}
}

Result.js

{
  "GroupMembers" : [{ }, { }],
  "_id" : ObjectId("5253f6dd89f6fc8a1c70fd72")
}