Here's a way I know to replicate this effect.
1. Make a door, and name it something. Hide it in an enclosed room somewhere and take away its sounds. Make sure it can still open.
2. Add the following to the door:
OnDoorOpen > Owner (client) > CenterPrint > Someone's at the door!
3. Make a brick that will work as your doorbell.
4. Put the following on the doorbell brick:
OnActivate > [Door name here] > DoorOpen
OnActivate > Self > Playsound > [Desired doorbell sound here]
5. When the doorbell is clicked, the person who created the door should be notified that someone rang the doorbell.