Hogwarts.

Hogwarts and Castelobruxo were schools that hated each other quite a bit, but they decided to try to leave that behind, and that's what I mean, they were forced to. The Castelobruxo seniors had to go on a visit to Hogwarts supervised by their teacher, and obviously they did it reluctantly. They arrived through a portal, which took them straight to the Great Hall of Hogwarts where all the Hogwarts students were, along with the Headmaster, Albus Dumbledore, who was waiting for Castelobruxo's arrival. In Castelobruxo they accepted all the countries of Latin America (except the USA), and Argentina was the head along with, obviously, Brazil (they're in that country, duh). In Castelobruxo they had managed to develop a new type of magic much more advanced, one that didn't need wands, simply; hands. Instead of a wand, they had a core, which took the place of the heart, and it was like a sphere of white energy. They were FAR ahead of the other schools, and that was well known.

I put it as "Hogwarts" so that they can put which character they want to interact with, and thus it will be more comfortable.