Create ticket over import/create_many.json

Hi all,

I am trying to create a tickets using{create_many.json endpoint}.
my issue is, inside the ticket I have this fields 

{

"tickets": [

{---------

-----------

"requester_email": "alexmurphy1516@hotmail.com",
"submitter_email": "alexmurphy1516@hotmail.com",
"assignee_email": "kazumasa.kumakawa@rubiko.tech"

------

-----}]

}

those email is not exist in my Zendesk instance, but when I am insering the ticket. I successd to make requester_emai submitter_email, but the problem is, I can't create 
assignee_email
either keep it null or assigne it to the account that I open to make import ticket.

Is there any solution to make assigne_email if it doesn't exist and asssigne it to the ticket when I make the import?

Thanks!