Say if Pakistan is divided into five nations, Balochistan, Sindh, Wazirstan, PakistanPunjab and NWF.
India can vastly benefit because:
1) India can have friendly ties with Sindh and Balochaistan. Trade etc.
2) India can have better access to MidEast oil via Sindh region.
3) Usual India hating elements in PakistanPunjab and Pak army will have their own conflict with Wazirstan and NWF.
4) Afganistan will influence NWF and keep PakistanPunjab enganged in usual military and terrorist conflicts. This will bleed PakistanPunjab for decades.
5) Kashmir will then naturally cool down.
6) PakistanPunjab islamists may then turn on china, possible chance for India to give China a permanent headache.
7) Might be possible for India to attack and claim back Sindhu valley in future.
Should India, Afganistan and Russia try to divide pakistan? It is certainly possible.