Specifies the name of the field or JMS property that contains a transaction indicator that is validated against the transaction indicator values. If this is not defined, all operations within a single message will be seen to have occurred within a whole transaction. If defined, then it determines the beginning, middle and end of transactions. Transactions defined in this way can span messages. This is an optional property.

fixed.txind={field_name|$jms_property}

For example:

fixed.txind=$TX_IND