If you are using the process code SD10, the underlying FM used for ORDRSP message type would be IDOC_OUTPUT_ORDRSP.
The first user exit that gets triggered inside this FM is EXIT_SAPLVEDC_004. This FM has the interface parameters which has all the necessary information that you are looking for via XVBPA/XVBAP/XVBAK.
Check the supplier code within this user exit and based on your conditions, if you determine that IDOC should not be processed, raise the exception "data_not_relevant_for_sending".
You can also check with your SD person to see if they can create an access sequence for the output type based on supplier code. If the required conditions records are not maintained for a specific supplier code, the O/P type will not be attached and hence the idoc will not get triggered assuming the idoc creation is based on a O/P type on the sales order.
Thanks,
Vikram.M