curl --request GET \
  --url https://staging.api.onenumber.africa/v1/recipient-groups/{reference} \
  --header 'Authorization: Bearer <token>'

{
  "statusCode": 123,
  "message": "<string>",
  "data": [
    {
      "reference": "<string>",
      "name": "<string>",
      "recipients": [
        {
          "reference": "<string>",
          "phoneNumber": "<string>",
          "email": "<string>",
          "firstName": "<string>",
          "lastName": "<string>"
        }
      ]
    }
  ]
}