Entire Chunk of Pakistani population directly and indirectly traces their origin to India.
The population of Bengalis is split between East and West Bengal...
However, that does not stop India from interfering in these two countries regardless of fall out...
2/3rd Pushtoons live in Pakistan and 1/3rd in Afghanistan with strong ties back to the tribes residing in Pakistan...however in Indian purview,
the same type of concerns are not valid for Pakistan to have a foot hold in Afghanistan....
I am not sure what size of dunce cap I should award you....