[CII-SR-464] - Only one BT-86 element is allowed on an invoice.
Stored validation assertion
(ram:PayeeSpecifiedCreditorFinancialInstitution or ram:PayerSpecifiedDebtorFinancialInstitution) or (not(ram:PayeeSpecifiedCreditorFinancialInstitution) and not(ram:PayerSpecifiedDebtorFinancialInstitution))