As we know, in NodeBB there is concept like "One Topic" has multiple "Reply" (Posts).
I wanted to implement functionality which provides facility for the user to make
"Comments" on each reply. So the hierarchy will be :
--> Topic
--> Reply
--> Comment 1
--> Comment 2
Most important is I wanted to do this using PLUGIN approach.

So Is there any similar plug-in available which can help me?
If I want to implement this then how should I start this? Any guidelines.