Maid of Honor
Krista and Katie played soccer together in high school and were reunited in university when they took the same train home. Conveniently, Krista, Katie, and Nicole were all in the same class block so they spent pretty much all day everyday together. Without these two, Krista never would have went to Greece and likely never would have met Josh.
Best Man
Michael hardly spent any time out of the womb before he had to deal with his older brother and partner in crime. As a team, Josh and Michael have caused problems and solved problems since 1997. These brothers have proven that great (or at least satisfactory) minds think alike, and despite the charges of nepotism, no one could fulfill the role of Josh's Best Man like Michael.
Bridesmaid
Nicole and Krista met the very first day of university. Krista couldn't find her orientation group and elected to join Nicole's instead of wandering around aimlessly. That turned out to be Josh's group too, but we didn't know that yet. Thanks to Nicole and Katie, Krista got another opportunity to meet Josh in Greece.
Groomsman
Christian and Josh have been close friends since elementary school and have collaborated on a wide range of projects over the years. These included being the contributing editors of a school magazine, members of a grade-six rock band (for one day), the designers of a series of brutal board games, and most recently, the masters of ceremonies for their G's wedding.