Were the passwords already existing in a raw list? If the list of users came from somewhere with existing passwords, were they already hashed?
If you are already assigning passwords to these users, I think you could just add raw passwords in to the password field and then they will hashed later?
I am not sure about that. But I am curious about your use case.
If you could share any more information about the source of the users you are trying to add, then please do so.