When two or more units are charging an enemy unit, the player moving them must divide evenly the frontage of the target unit between the charging units (Fig. 1). Also keep in mind that you cannot shuffle around the charging units so that their charges cross in order to bring in the strongest unit (Fig. 2).

Remember, the spirit of the game is the best guideline to follow, so try to do something that 'looks right' and is realistic, as opposed to trying to stretch the rules to create a weird situation which looks obviously wrong like the infamous 'clipping') and gains some unfair advantage to one player.