Is there a way to derive a single score of a given team?

[Nelluk]

I'd like to calculate a leaderboard of teams. Is there a function to derive a single TrueSkill number for an entire team?

[rmarquis]

According to TS paper:

The performance of a team is the weighted sum of the performances of its players, where
the weight is the fraction of time the player spent on the team.

[sublee]

The weighted sum layer is implemented in TrueSkill, but there's no public API.