Meeting of the Five

The mana created by Meeting of the Five can be spent on any portion of the cost for a spell with exactly three colors, including any generic cost component or additional costs it has.

You may cast any spells that have exactly three colors from among the cards exiled this way, even if they aren't the same three colors. For example, you could cast a spell that is white, blue, and black, then cast a spell that is black, red, and green.