Access current system or target system ID in message mapping

Hi.

I have a requirement to map three different constant values to Sales Org field, depending on whether the system is D, Q or Prod.

This needs to be done in the message mapping section of the Interface along with all the other mapping logic.

Is there any way how we can access the current system ID or the Target system ID (XI is communicating with target, in this case, ECC, using RFC receiver Communication channel)?

Please help.

Thanks.

Anuradha.