How to conditionally execute rtf template inside for each loop BI Publisher version 11

I have payment attachment that I want to only print if flag is set to Y, and bypass if set to N (and Not get a blank page.)

Check write program produces xml with as many invoice detail lines as are associated with check. However, only a certain number can fit on the actual check stub. If more that than number are present I want to print attachment with only invoice details and not check. I have to process the same xml through two separate templates, as the check goes to one printer and the stub to another printer. I do not have Enterprise edition of BI Publisher.