Get outstanding balances for multiple orders

{
  "orders": [
    {
      "orderId": "<string>",
      "balances": {
        "orderWriteoff": 123,
        "unallocated": 123,
        "institutionInvoiced": 123,
        "institutionUninvoiced": 123,
        "patientResponsibility": 123
      }
    }
  ]
}