Rondee assigns each organizer and each invitee their own PIN.
Rondee also assigns a listen-only PIN to just the organizer. Any number of people may call in using this PIN to hear the conference. Like all Rondee PINs, this one is private unless the organizer chooses to share it with others. What this means for you as the organizer of a Rondee conference call:
1) for the folks you want to participate by listening and speaking: invite them as you normally would using Rondee
2) for the folks you want to attend by listening only: simply email them the listen-only PIN and tell them when to call in