When a cavalry regiment charges can other cavalry regiments behind them follow? If they can't a cavalry charge could result in some of the units in a group becoming out of command.

As far as I understand it, they cannot, and so one part of the unit group might end out of command.

I agree with Klaus.

You may recall your group next turn, during Formation change, after passing a Moral Test, even if out of command and try to move it back in formation and in command. Negative point, at the end of the recall, the group will be disordered.