Blain,
How the country invaded its own state, well first you need to get some inside into India's history then you would know that Hyderabad which were a part of Deccan Empire rules by Nizam's which were autonomous part of India during British rule. When Britishers left India after Indian Independence, they left it to Nizam whether he would join India or remain a Independent state of its own. Nizam wanted to be Independent, even though Nizam itself was having more money than India itself but didn't have army big enough to fight Against newly independent country, which forced which in History of India called "Police Action" in which they invaded Deccan and absorb in India, like what US did with Texas, country invaded its own state in your words.

Well, I agree with Zeeshan, Shia and Sunni are merely a division which is widening by media, specially the western media.
This is not the new thing for the West to divide and rule, so they game plan still the same, they rule India by dividing Hindu and Muslim, other wise India was the most prosperous country before the bustard Britishers came in, under the Muslims rule they were prosperous for thousands of years. Then the bustards’ Britishers divided them and still they are fighting.
The same way they want the oil from Iraq and they divided the Sunni's and Shia's.

Till yesterday nobody in West know the real difference between Shia and Sunni and now the bustard’s American play a dirty game and divided the society for their own advantage.

I believe they should forget what ever little difference between them and kick the westerner out of the country then build new iraq.