Hello,
If ur condition is not satisfied (which can be validated using Extended RD or RD) then why don't u just ignore the receiver itself so that u can avoid executing ur idoc mapping?
For ur reference:
http://help.sap.com/saphelp_nwpi711/helpdata/en/48/ce2a423a8e5430e10000000a42189b/frameset.htm
Edited - Adding SAP help ref.
Thanks
Amit Srivastava