question

As you may notice that Multiplayer 2.0 is designed for session-based games, which is perfectly suitable for MOBA games on the market, usually even with different teams, players are allocated randomly into a team if it is using a matchmaking system. (red/blue team in League of Legends, Radiant/Dire in DOTA2), the guaranteed team selection is not supported natively. However, there are workaround solutions.

1. Divide the matchmaking process into 2 steps. First, the player (selects Team A) will match with others who also select Team A. The server will randomly pick a member as leader to create the second matchmaking ticket, to match with a Team B.
2. Another workaround will only require 1 matchmaking queue. Based on the requirements, if each team have 5 members, we can configure a match total rule, for example, Min and Max value are 505, where players who select Team A should have an attribute of 1, and players who select Team B should have an attribute of 100, hence there should be exact match of 505. Meanwhile, in this scenario, the team defined in matchmaking won't work. The server should determine the team via their attribute values in the ticket. It is more like the scenario in the official documentation -- Host/Searcher or Role Based Requirements