Speaking from experience, they may have enough players to fill every one of the teams available, provided they aren't all playing on the same day. Adjacent divisions don't play on the same weekend. Middlesex qualified for the preliminary in the top three divisions and all three matches were due to be played on the same day. By the time a few U180 players had been lost to the Open and lots of U160 to the U180, there wasn't a lot left for the U160.Mick Norris wrote: Middlesex spread themselves too thin in the Preliminary round - they beat us (G Man) in the Open, but lost in the U180 and defaulted the U160 (possibly disproving the theory that the SCCU counties have enough players to fill every one of the teams available)
Not that it was SCCU, but in 2009 Yorkshire reached the final in the top three divisions and won all three matches, so somewhere it is possible.