With the new finAPI release v1.10.0 it is now possible to make collective money transfers by using the service "Request SEPA Money Transfer". In case that you want to submit not just a single money transfer, but instead do a collective money transfer, use the new field “additionalMoneyTransfers” to pass a list of additional money transfer orders. The service will then pass a collective money transfer request to the bank, including both the money transfer specified on the top-level, as well as all money transfers specified in this list.
Please note that the new flag “collectiveMoneyTransferSupported” in the Bank Connection Resource, which indicates whether the underlying bank connection supports submitting collective money transfers for its accounts, is set by default to false for all existing bank connections. The user has to update his existing bank connections to make finAPI revalidate the field.