Some thinking gave rise to this idea. Give it a shot:
When a Bail is rolled, the player has two options:
Either withdraw all figures in the same terrain feature by 3"
Bail one figure as per the normal rules.
Isolated figures on their own MUST bail as per the normal rules.
Withdrawn figures count as having Flinched for firing purposes.
This gives the player the choice of either falling back in good order when the fire gets unbearable or a single man panicking and fleeing.