ATTENTION: If the selected account has set antispam rules, they will be overwritten - not only added. The result is, that selected accounts with cloned rules have set the same rules as the postmaster mailbox.
After clone antispam rules the content of particular parts is changed:
Antispam rules can't be cloned from postmaster to email aliases that have not set any antispam rules. It is neccessary at least to save antispam rules for the email aliases in Administration section, see Antispam and email aliases. It is impossible to set antispam rules by this way for aliases with no antispam rules, at first you have to set antispam rules for the aliases in the section Administration > Forwards in the column Antispam.