Help! WANT FULL LINEUP in car divisions for freeplay

To any forza staff,

Why is it that in freeplay, the starting grid will only have cars with pp closest to mine? My skill is at a level where im trying to use the lower pp cars(rebellion toyota) but I still want to race with the good ones of the same division. Yet the starting grid has only the weakest cars (Mazda 12/80, corvette prototype, ford prototype). Is there a fix for this? Its bad having only 3 different cars racing me!