A filter module for a WOSA/XFS transaction processing system is disclosed. The system includes a WOSA transaction manager which is responsive to transaction requests from at least one application. A service provider layer is adapted to relay transaction requests passed from the transaction manager to associated hardware for execution. The filter module is adapted to intercept transaction requests from the transaction manager to the service provider layer and to process the requests. The filter module is further adapted to intercept transaction responses form the service provider layer to the transaction manager and the at least one application and to process these responses.