This will be singles randoms between every single generation of Pokemon in a Bo3 or Bo5 format. Each Match will have Multiple generations of randoms being played and here is how it would work.

Game 1
Higher Seed Would ban 1 Generation of the 9 Generations of Pokemon. Lower Seed would ban 2 Generations. Higher Seed then Bans another 2 Generations. Lower Seed Bans Another 2 Generations and Higher seed then chooses which Generation Would Be played.
Game 2
Winner Bans the 4 Generations of Pokemon and the Generation that was played is Automatically Banned. Loser chooses from the remaining 4 Generations
Game 3
The 2 generations that were played on are banned, winner bans 3 Generations. Loser chooses from the remaining 4.
Game 4
The 3 Generations that were played on are banned, winner bans 3 Generations. Loser chooses from the 3 remaining generations.
Game 5 The 4 Generations that were played on are banned, winner bans 2 Generations. Loser chooses from the remaining 3 Generations.