[DS2] Close Assault question

I was wondering about close assaults and whether they need to be carried out
as a unit, or can single elements within a unit perform one while other
elements take other actions (such as provide covering fire, move, or retreat
shielded by the assault)?

On page 18 it says "Different elements in the unit may choose different
options;..." Which makes tons of sense and provides excellent command
flexibility.

But every mention of close assault specifically discusses it in terms of
UNITS, so I am inclined to think that it is a not an elemental option.

But on page 34 close assaults are described as combat actions; "One CLOSE
ASSAULT may be made by a Unit during its activation, counting as its Combat
Action." As a combat action it may slip back into the realm of options to
consider at an elemental level.

It is too late to address the specific instance that came up 2 days ago, but
for future reference: is Close Assault a special combat action that functions
only at the unit level, or can elements close assault individually?

This is my first post to the list - so if this is old news - be gentle
:)

(FYI, we let my opponent carry out the assault. I held my ground and wiped out
the charge.)