[rules-dev] Firing a Default Rule

Hi, If I have say a set of 10 rules out which 9 fire based on some condition. However the tenth rule, to which I set a saliency of -1 to make it fire last, should fire if none of the other 9 rules cause any change to a particular property of the asserted bean object. Is there some way (command) using which I can achieve the same from within a DRL file?