You can do it in a Xlate. First off, I like to remove the BULKCOPY statement and use PATHCOPY where needed. Then when you are iterating through your IN1 segments, you can use whatever IF logic then then PATHCOPY the approriate IN1 segments you need based on some value in the segment itself.
If you leave the BULKCOPY in, your iterate will be to PATHCOPY @null to the IN1 in order to remove it from the outbound side since it was copied in by the BULKCOPY.
Hope this helps.
