[rules-users] how to fire a subset of rules in KB?

Hi all, I'm a newbie for drools. And i want to know how to fire a subset of rules in KB, suppose there are three rules named A,B,C, and I want to fire rule A only. by the way, suppose there is a drl file containing rule, and i have set up KB, and call fireAllRules through statefulKnowledgeSession. After that, the rule file is changed, how to load rules dynamicly? Is there any solution? Thanks in advance! best regards. 2010-06-07 wenjinchao