Custom Event From Server

How would we use Custom Event calls into PX from the product database rather than the user terminal? That is to say that if a custom event is triggered and sent from the user terminal back to Gainsight it would make sense that Gainsight could identify which user the event is associated to. But if we wanted to send database events to Gainsight on a system side trigger. How do we ensure the event is tied back to the particular user?