Autonomous States with common currency and defence umbrella?

Reorganization of States  on linguistic basis removed the Kannada, Malayalam and Telugu speaking regions from the Madras State. And Annadurai had to change the call for an independent Peninsular State to an independent Tamil State. 

Remaining in the Indian Union meant economic backwardness and linguistic subjugation.

But the China war brought changes to the Constitution. 

The sixteenth Amendment banned, parties with autonomy ideals, from contesting elections. Annadurai vehemently debated against this amendment in parliament, but could not stop it from being passed. 

And Annadurai worked at better cooperation between the Southern States. 

- Wikipedia