I ran into this problem in a game recently.
A Division Order was given to a group of infantry units to Charge the enemy to their front. Some of the enemy were close order troops and others were open order troops. Some of the open order troops Evaded. At the end of the Turn the chargers whose target had evaded were more than 6" away from the chargers that had contacted the close order line troops who had stood.
The rules say that units moving with a group order must start and finish the turn within 6" of each other.
It doesn't seem to be optional to not complete the charge move if the enemy evade. But if they move their full distance they break the 6" rule?