NWScript:

///////////////////////////////////////////////
// Multi-NPC Conversation Trigger
// coded by DragonTayl
///////////////////////////////////////////////
void main()
{
  object oChick1=GetObjectByTag("fc_CultChick1");
  object oPC=GetEnteringObject();
  /* Check to see if it's a PC entering, this if
     can be removed if you wish to have it triggered any
     time even an NPC goes through the listening area,
     but be aware that the conversation starts over any
     time a valid object enters the trigger area. */
  if (GetIsPC(oPC))
    {
      /* Note that this is the first line of the
         conversation. This is done so that there isn't
         a long pause between the PC entering the area
         and the first line of the conversation (while
         the engine waits for the NPC's Heartbeat event).
         If you want a pause, simply comment out the next
         line. */
      AssignCommand(oChick1, SpeakString("He's such a lug."));
      SetLocalInt(oChick1, "iShowLine", 1);
    }
}

NWScript:

//::///////////////////////////////////////////////
//:: Default: On User Defined
//:: NW_C2_DEFAULTD
//:: Copyright (c) 2002 Bioware Corp.
//:://////////////////////////////////////////////
/*
    This specific OnUserEvent script plays out a
    Multi-NPC Conversation.
    Coded by DragonTayl
*/
//:://////////////////////////////////////////////
//:: Created By: Don Moar
//:: Created On: April 28, 2002
//:://////////////////////////////////////////////
void main()
{
    // enter desired behaviour here
    // 1001 = OnHeartbeat Event.
    int nEvent = GetUserDefinedEventNumber();
    if (nEvent == 1001)
      {
        /* Add more objects here if you wish the
           conversation to have more participants */
        object oChick1=GetObjectByTag("fc_CultChick1");
        object oChick2=GetObjectByTag("fc_CultChick2");
        int iLine=GetLocalInt(oChick1, "iShowLine");
        // Check to see if the trigger started the conversation
        if (iLine > 0
            && IsInConversation(oChick1) == FALSE
            && IsInConversation(oChick2) == FALSE)
          {
            /* This is the meat of the conversation.
               Change the text in the SpeakString(s) to
               the lines of your conversation. Simply
               remove cases if your conversation isn't
               this long, add them if your conversation
               is longer. Please note that the last case
               needs to increase the iShowLine variable or
               the last line of the conversation will loop.*/
            switch(iLine)
              {
                case 1:
                  AssignCommand(oChick2, SpeakString("Tell me about it. Always running into things."));
                  SetLocalInt(oChick1, "iShowLine", 2);
                  break;
                case 2:
                  AssignCommand(oChick1, SpeakString("And his appetite is impossible"));
                  SetLocalInt(oChick1, "iShowLine", 3);
                  break;
                case 3:
                  AssignCommand(oChick2, SpeakString("I don't know what to do with mine, either."));
                  SetLocalInt(oChick1, "iShowLine", 4);
                  break;
                case 4:
                  AssignCommand(oChick1, SpeakString("I have thought about sacrificing him. There's always fresh meat around to replace him."));
                  SetLocalInt(oChick1, "iShowLine", 5);
                  break;
                case 5:
                  AssignCommand(oChick2, SpeakString("Really? How would you get that done?"));
                  SetLocalInt(oChick1, "iShowLine", 6);
                  break;
                case 6:
                  AssignCommand(oChick1, SpeakString("Easy. Most of the Superiors are all too eager to make an example of someone."));
                  SetLocalInt(oChick1, "iShowLine", 7);
                  break;
                case 7:
                  AssignCommand(oChick2, SpeakString("But they don't always listen and might sacrifice YOU!"));
                  SetLocalInt(oChick1, "iShowLine", 8) ;
                  break;
                case 8:
                  AssignCommand(oChick1, SpeakString("They do what you want if you get intimate with them."));
                  SetLocalInt(oChick1, "iShowLine", 9);
                  break;
                case 9:
                  AssignCommand(oChick2, SpeakString("Not a bad idea. I know just who I'd use..."));
                  SetLocalInt(oChick1, "iShowLine", 10);
                  AssignCommand(oChick1, ActionPlayAnimation(ANIMATION_LOOPING_TALK_LAUGHING, 1.0, 5.0));
                  AssignCommand(oChick2, ActionPlayAnimation(ANIMATION_LOOPING_TALK_LAUGHING, 1.0, 5.0));
                  break;
              }
          }
      };
    return;
}