Transmitting user preferences to server

In the settings that each player sets in my game, I have several options that should be transmitted to the server before the team is chosen for a player, like the default “preferred team” number.
What is the best way to transmit these local settings (saved via a USaveGame object) to the server before the post-login operation is done?
The server could sent a multicast request to all the client, and expect them to send it back their preferred team in order to make them appear in the right team, but I would expect a possibility to transmit some settings from clients to server while logging into a game… Is it possible?