In the interest of all, golfers are expected to play "ready golf". Nine-hole rounds taking longer than 2 hours, 15 minutes will be considered as moving too slow and management reserves the right to ask a group to speed-up its play or, kindly, let groups behind them through.
Exceptions can be made if a slow group is being courteous and letting faster groups play through ("it is fine to take your time as long as you're letting people by").