Integration is more than just the conversion of data. Messages must be received, analysed and referred. They have to backed-up and where necessary duplicated in order to be available for parallel processing steps.
They must be converted and sent to the corresponding systems or recipients. Where necessary the arrival of data should be registered with the sender.
All transactions must be documented and any errors must be reported immediately.

These tasks should be executed by a central system to ensure clarity and ease of maintainance.