For those unfamiliar, Slayer is (imo the best) one of the top $$$ machines and pairing it with a budget grinder is a classic sign the owner doesn't know a thing about coffee. Often the grinder is more influential than the espresso machine.
And how I mention "Group 3" that means it has three brewing heads. They were using a ~$20-30k espresso machine paired with a run of the mill budget grinder.