When beating to weather, a starboard boat is an obstruction to a port tack boat. PL has rights over PW (windward boat shall keep clear), and can hail for
pw to tack so PL can clear the obstruction (PL must then tack immediately). IF PL elects to go behind the obstruction, he must give PW room to also pass behind the obstruction. He cannot "peel off" PW on the starboard boat.
Make sense?
I do not have the rulebook in front of me, but assume this is the situation you are referring to. If not, please excuse the intrusion.
Ken