[exim] Exim: Select smarthost on basis of receipient address

<https://mail.google.com/>Hello,

I know smarthost selection can be done on basis of sender_address.
i found following two URL's are good resources for that.

http://www.volker-wegert.de/en/node/35
http://www.tgunkel.de/docs/exim_smarthosts.en

But is that possible on basis of recipient address? I need whenever my
domain user send an email to same domain user it will relay to another
server e.g. abc@??? sends an email to xyz@??? it need to
relay on mail.example.com SMTP.
And when my domain user sends an email to external domain it will go
through locally by dnslookup. e..g abc@??? sends an email to
hotmail,yahoo, gmail it needs to go through locally from mail1.example.comSMTP.

I want to acieve this because mail.example.com SMTP is on USA DC and
mail1.example.com SMTP is on china. And when china user normally sends
emails to external domains normally in china and currently they have to
connect USA DC mail.example.com and this yields mail sending issues along
attachments. I want china users should able to send emails directly from
China DC by using mail1.example.com

Also, i tested successfully relaying from mail1.example.com to
mail.example.com primary MTA which holds all users mailboxes but it
relaying every email to US DC. I want relaying only for @example.com and
for external domains email should go directly from china DC
mail1.example.com SMTP through dnslookup router.

Thanks in advance for your help.