Edit Season > Grouping Schemes > Max 3 (or 4) Player Groups (XX Groups) … in your case, sounds like 9 groups would be a minimum, though you can go higher if your location has enough machines to accommodate everyone. Please don’t hesitate to let me know if you have any questions or problems with this.
Just FYI: note the “Support” block on the bottom of the manager menu:
Questions? Problems? Just wanna say hi? Contact us at firstname.lastname@example.org!
Those inquiries get specially flagged on my phone… I may or may not be able to respond instantly, but it’ll almost certainly get faster response (from me, anyway) than general posts here (or Pinside, etc).