How to prevent players from playing in the U19 squad?

[swanseaboy93]

I know the coach asks which players you want to play in the U19 squad out of the senior squad, however I was wondering whether there is a way to actually prevent any of my players from playing in the U19 squad as sometimes I don't allow the list of players from my senior squad available to play but a few do. I want to stop this as my best players end up missing my important first team games and play in the U19, even if they haven't had injuries and are fully fit.