Here's a very rough guide. I don't know all the categories.

Maidens
Class A-D i think?
Class 1-6
Open Handicaps
Metro races such as Restricted Metro Wins 0,1,2,3(3yo+, 4yo+; f&m, C&G); Various 2yos races, Welters, Flying, Quality, listed.

Then you have group 3 thru to group 1

But $$/race gives you a good idea anyway.