Email Assist: Add more than 1 name in the TO line

One of the ways we are using email assist is for our on boarding emails.  It seems that there is a restriction and only one 1 name is allowed for the TO line, however multiple are allowed for the CC line.  We'd like the ability to send one email TO multiple people vs having to add the other recipients to the CC line or send the same email multiple times.  Is this restriction a bug or intended functionality?