We have the base Dominion set along with the Alchemy and Prosperity expansions. The rules cover 2-4 players, but elsewhere it implies that up to 6 players are allowed with expansions. Nowhere we could find does it explain if 5 or 6 players have a different setup or end game conditions.
Do you need a different setup for 5 - 6 players in Dominion? I get the impression that adding the Colony and Platinum is required, but not sure if the starting cards or end conditions change. Or is it a different expansion that allows for 5 - 6 players?
I am open to "official rules" and "recommended rules."