There are several types of bets and the recommendation is people use the Group A horses to bet vertically (Daily Doubles, Pick 3, Pick 4, Pick 5 and Pick 6. Group A horses are set up to be 5-1 or better with respect to odds. Group B represents horses ranked between 5-1 and 10-1.
Betacus positions races horses by rank and divides horses into A and B groupings. The positioning of the horse is similar to an abacus which is where the name Betacus comes from.