Anyway, the conflicts started with the oligarchies in the south of that territory, who fought for the land ownership and some other economic interests, which were closely linked to the state of São Paulo, due to geographical proximity, and its development. While the capital of Mato Grosso was well established to the north of the state, the people of the south did not feel represented by their authorities, governance or guidelines.
Thereby, many armed conflicts and political pressure took place over the years until, finally, the territory was splet into two, which occurred for other reasons that they did not necessarily involve the cause of the people of the south, but for reasons of national security and borders and foreign policy with neighboring countries.
Regarding the states of Rio Grande do Norte and Rio Grande do Sul, although they have equal names, distinguished only by the cardinal point of the geographical location to which they are based, these two states do not share any individual or proximity history, not even by the "river" (Rio, in portuguese) that, supposedly, would have inspired their names.
In fact, they are states that are thousands of miles apart, with totally different cultures and histories.
I think the only bond and involvement they share is because of the national unity, which makes up the Federative Republic of Brazil.