There's some contention in my group about whether all three units consolidate or just the unit/model that dealt the killing blow.
The procedure would be as follows:
Units A, B, and C charge
Unit A piles in
Unit A fights
Unit A consolidates
Unit B piles in
Unit B fights
Unit B consolidates
Unit C piles in
Unit C fights
Unit C consolidates
Piling in and consolidating are part of the unit's activation on the fight phase, so the first activated unit will completely finish consolidating in accordance with the rules for doing so before the next activated unit gets to being piling in.
So the answer to the letter of your question is yes
. Unless otherwise forbidden, all units that charge get to fight, pile in, and consolidate even if they have no valid targets to fight.
However, the answer to the spirit of your question is "probably no", only the unit that scored the killing blow and any that follow it consolidate meaningfully, because units that didn't destroy it will generally have to be consolidating into the still-yet-undestroyed unit or remaining stationary.