send Response Automatic

Hi,
I have an integration escenario. SAP R3 send some dependences message to SAP PI and this to a MockService(SoapUI). Now Once the last message was received and the response was sent back to SAP XI, SoapUI must automatically send another(separate) message to SAP PI.i mean, SoapUI must acts as the request Sistem. how can i do this??

Thanks
Rodrigo P-.