Invite the leaders of two nation to the Friendship Castle where they could meet, talk about their people and the like. And than they later on can invite the others to their own kingdoms.
Twilight decided the first ones to be the King of Abyssinia and King of Ornithia. Abbyssinia was at this point an ally to Equestria and while Ornithia was secluded, old books of it talked about a nation that’s known to be friendly to anyone and has interesting customs. Everything can only go great, right?
Well, except for the fact that the old Ornithia is gone as it was overtaken by pirates hundreds of years ago and now it’s a pirate nation. Oh, and Abyssinia known to be “strangely litigious”, not tolerating any unlawfulness of any kind.
Not the best combination for Princess Twilight to start of with.