7 A drivers Blaney, Larson, Byron, Hamlin, the remaining 3 can be any of the following (Truex, Buescher, Logano, Elliot, Keselowski, Busch, Chastain, Reddick, Bell). Those 7 not selected for the A group then are B divers along with.
B). Wallace, Brisco. McDowell, Gibbs, Suarez, Jones, Dillon, Bowman, Stenhouse
(C) All the left overs.
8 A drivers are to many--you don't need 72 starts in that group for 36 races (36 starts)
B group minimum of 8 drivers needed and once you get past 7 in that group

( 72 starts)
C group Preece, Cindric, van Gisbergen, Berry, and what ever. (36 starts)
7 A drivers (63 starts)
13 B drivers (117 starts)
? C drivers (36 starts)