If I were to ask:
Which children did you bring?
and you respond:
I brought both Adam and Billy.
The "both" implies not only that you brought two children, but that you brought your only two children (that the whole set was brought).
If, however, you had more than two children, neither:
I brought Adam, Billy, and Charlotte.
I brought all of Adam, Billy, and Charlotte.
would have the same connotation that you brought all your children. The first gives no idea how many children there are total, and the second sounds more like you brought "all of" each individual item. Is there a word that has extends the meaning of "both" to more than two?