[rules-users] Defining fallback rules

Hi all, I'm currently puzzled on how to implement a sort of fallback rule. In my scenario I have a couple of articles and payments related to those articles. Now I need to distribute royalties to the authors of these articles. There's a common business logic which says "distribute X percent for articles of type T, Y percent for articles of type S and Z percent for all other articles". At first, my approach was to write the rules like this (omitting a rule for type 'S' for the sake of brevity): rule1 activation-group "article1" salience 100 when $article : Article(type == 'T') $payment : Payment( article==$article ) then account(x%) end rule3 activation-group "article1" salience 0 when $article : Article() $payment : Payment( article==$article ) then account(z%) end However, I quickly found out that the use of activation-group will then only consider all articles of type T and ignore all other fact-combinations. Retracting payments from the WM is also not feasible since there may be other rules that should work on them. I also cannot write the last rule as Article( type != 'T', type != 'S' etc) since new article types may be added later on and it would not be manageable to update all previously written rules (which may very well number in thousands in the future). Now I'm a bit stuck on this issue and would welcome any hints. Best regards Marcus