Originally posted by WC
erm.. yes. System already exists, that's called the Finals. 
Before the finals, you compete in the Heats to determine your
lap time... best group goes into the A-Final, next lot go B-Final etc.
The Heats is a timed event, so you're running against the clock
only (for best time) and *not* competing against another car.
The cars get beeped off one at a time... aka "qualifiers".
The Finals is where you race head-to-head. Everybody starts at
the same moment, and the winner is the one that does the most
laps in the fastest time.. aka "Mains".
the clubs are dividing drivers into different group, that is why some groups only have 5 cars, some have 13 cars, if they cannot race together, there will be three races. long day, but boring .
another way is to group them into two groups, faster group. top 10 drivers. and the next group will be 8 drivers.
some stock car run faster than pro touring car. so they can race together. can't they?