[rules-dev] guvnor - adding own operators in conditions for eligibility rules

I like to add or change the existing operators in the condition part for eligibility rules. - equal to - not equal to - matches - sounds like For instance I like to distinguish between reference compare "==" and deep comparison with "object.equals()". Any ideas how I can achieve that? Any hints where I can have a look in order to start with that? (links, class names etc.) Thank you in advance regards Mark