You can write a matchmaker or use a third-party matchmaker. When you use a matchmaker, the selection of the fastest payload response is programmed into its client-side service. 

For example, you might run a payload in the United States and a payload in Europe. 
When a player connects from Russia, the matchmaker's client-side service sends a message to all available payloads and then provides a list of payloads sorted by their response time. The client-side service then selects the payload with the fastest response time to connect the player to.