Sorry, I don’t understand. If you place an NPC reply after an NPC reply, why would the widget think that the dialogue ended? It would do exactly what you’re looking for: display line 1 and a continue button. After you click “continue”, it will go to line 2. Etc.
What do you mean by “Player Reply is the same”? There is no player reply in this scenario, it’s just an NPC node after an NPC node, after an NPC node.