Several problems will occur that will have to be overcome,
If anyone starts using the race theory as i posted.

The day and date and name of the race will have to be entered,
The problem being that race clubs regularly rename,
Races as they attract new sponsors to the sport.

So a gr=3 race may be in 2007 may be the barny stakes,
In 2008 it may be the mark stakes in 2008 it could be the garyf stakes.

Still the same race but might have a different name the following year(s).

The other problem is each year the races change group status.
Each year a select committee sits down and assesses each races category.

I only know 2 of the criteria.

1= Quality of the horses the race attracts.
2= The prizemoney the club has to offer for the race.

There's probably other criteria i just don't know them.

So what in 2007 may be the GR-3 Barny hcp
May be in 2008 the GR-2 Garyf hcp etc

Your time honoured races like the Caulfield + Melbourne cup,
The Oaks, The Derby, The Guineas, etc are all ok but the rest,
Of them could change name and Group Status.

The name change can be checked but a race going from a ,
Listed Race in 2007 to a Gr-2 in 2009 will obviously attract,
The better class horses meaning when it may be useless,
Following the race when it had Listed status only would then have,
to start on that race again at the different group level.

If it were me i would probably concentrate on the state where i live,
And maybe restrict ones self to the gr-1-2 races only, which,
Once established you would think only go up or back one grade,
Or that plus the time honoured races for consistency.

Only a suggestion but these,
things will always be happening.

Cheers.