Must a supporting unit (eg, Principes) always make a charge against the unit with which the supported unit (eg Hastati) was in combat? Can the Principes "see though" the hastati in order to declare a charge against, for example, the flank of an enemy unit once the Hastati has charged forward and the Principes could actually contact that enemy flank?
To put it another way, my Hastati draw parallel to an enemy unit A's flank but see a charge target straight ahead. They block the principes' LOS to enenmy unit A, which is kind of diagonal to the principes anyway. Can the principes "see through" the Hastati to declare a charge (as in Maniple #2), or can the Principes only declare a charge "through" the Hastati in order to charge that flank?