A question about reporting

I was in a race recently around Prague and while people were cutting the track, it was mostly in the esses that were only made dirty a year or so ago. Not my issue. I don’t really care about that problem, the issue I’ve got is one guy was wrecking other people hard. He slammed me into a wall via a no-brake manuver three times, pit manuvered another person, and did the no-brake at the end of a straightaway to two other people. I just want to know if I uploaded the replay, would everyone who was cutting (basically the entire lobby) get banned, or just the guy who was intentionally wrecking people?

And if I did want to report someone, what is the procedure for reporting?

There is a section on the Forza support site where you can report wreckers. Fill out the ticket and upload your replay of it. T10 will only look at the one being reported, they will not bother with anyone else in the lobby.