Players are grouped together based on rank. The higher your rank, the more valuable your reward for winning will be. Your military achievements in Megapolis will be taken into account, and affect which opponents you are paired up against. You cannot switch groups when the race is already going. But if you keep actively playing, by the time the next race comes around, you might end up in a stronger group, and be able to compete for more valuable prizes.

Have fun playing the game!