This method will return all the reservation data for each reservation in a group.
|business_code||Integer||This is the business we are working within.|
|invoice_id||Integer||This is the invoice_id of the invoice we want to retrieve.|
|format||enumeration||(optional) Set this value to "xml" for XML raw formatted output, "xml-clean" for XML tidy formatted output or "json" for JSON formatted output. If not passed, "xml" is used as a default|