[rules-users] New Operators

Hi Guys , I am using the latest version of drools fusion . Is it possible to create new operators ? For example I want to make the logic rule OR i.e : a :- b;c. I know I can make a rule for it like this :: rule _Rule when $a Event() $b Event(this after $a || this before $a) then //.. end can I embed this rule to make more complex logical rules ? say for example I want to represent the following rule : Exp :- (a AND b AND c) OR (d AND e) One more question :: how can I represent the not operator ? i.e : a :- b AND (NOT(b)) Thanks, Khalil Hafsi