From my best recollection, I have not had a multi-generational referral come directly from myself (but we have seen some from my wife's time in PowerCore).  The multi-generational referrals that we have seen have always come from a place of impression and execution.  

For our business, we have had many clients from PC referrals that recommended friends and family that recommended others etc to the point where I know we have 4th and 5th generation but is impossible to track.  This started with the original referral being impressed with our preparation, organization, and ultimate execution of their need.  From that experience they were happy to share with their friends and family that we were knowledgeable and competent.  This chain of execution is ultimately how your word-of-mouth marketing takes off.

For my team, I have had friends tell me that Brenna's presentation was so organized and impressive that they have already sung her praises to their friends who inquire about realtors.  That meeting (although not gaining their business for multiple reasons) created a lasting impression that has made them happy to pass her information along.  Even if the business is not secured that day, the preparation and knowledge that the client meeting showcases will faciliate those multi-generational referrals.