You can do this with the dialogue editor..
1: Create a new dialogue with the 3 NPC and the GROUP_Players as the speakers.
2: Create your dialogue but do not assign the GROUP_players to any of the nodes, just assign who is speaking at the time.
3: Assign this new dialogue as the "default dialog" for each of the NPCs.
When the player clicks talks to any of these NPCs they will get into the dialog but will only be able to "listen" and will not get the option to participate.
hi, i did exactly what you said, but it does not work. I tried for a very long time, but I do not see the mistake I make