Abstract: A node managing unit (11) selects, for an event associated with a sub-context of a specific context, an event distributing unit of a plurality of event distributing units (12, 13), which distributes events towards queues for the specific context. The selected event distributing unit selects a queue for the sub-context, which is associated with a rule engine unit of a plurality of rule engines units (17, 19), which comprises a rule execution unit associated with the specific context. A rule managing unit of the rule engine unit, which receives the event from the selected queue for the sub-context, selects the rule execution unit of the plurality of rule execution units, which is associated with the specific context, and delivers, to the selected rule execution unit, a particular rule of a rule set associated with the rule execution unit, within the associated sub-context.