Death in the Dark Continent - closing fire?

[Redshank]

Tried DitDC yesterday for the first time. My opponent and I enjoyed it, but came away with a question about closing fire in response to a charge.

I understand closing fire from the target of the charge is handled through the mods to the attacker's melee roll itself.

But there is also a reference to friendly nearby units being able to add their own closing fire.

How does this work? Is it handled out of normal turn sequence (as moving/charging is before firing)? Or if friendlies' closing fire happens in the fire phase, and it adds enough DMs to prevent the chargers being able to close, do you "rewrite history" at that point and move the charging unit back 6" from the target?

Any advice gratefully received!

[SteveBurt]

I think only the target of the charge gets to fire, and that is a modifier on the melee roll