Hello, It seems that Drools 3 performs better for us (at least for now...) then Drools 4. Drools 5 was not yet tested. I'm wondering what is the most efficient method of implementing Drools 4 activation-group[1] feature using Drools 3 ? In my system, in order to complete the match session I'm using a combination of 2 rules one (and only one!) of them must pass so that the match will be successful. I would like to use a XOR between them and give higher salience to the first rule which is a light weight version of the second. My motivation is keep drools from evaluating the second more complex structure of the "heavy" rule as fast as possible. So, to summarize - How would you guys recommend implementing the XOR structure between 2 Multiplicative inverse rules ? Thank you, Maxim. [1] http://downloads.jboss.com/drools/docs/4.0.7.19894.GA/html_single/index.h... -- Cheers, Maxim Veksler "Free as in Freedom" - Do u GNU ?