you cant, but at least they aint socialising with them 6 hours a day 5 days a week, anyway, there are options, do whatever pleases you most.
master g, that pic is awesome hahaha but you know what, at the end of the day you can't stop your child being influenced by whoever, its all part of growing up and becoming an individual, you just got to hope that you raised your kid well and taught them whats right and wrong, and hope they are strong minded enough not to be THAT thick ¬_¬ x