[Exim] destination host variable

Dears
Thanks about my previous question.
Now I have problem with exim with variable inside exim contains
destination host I need to use it
In inside exim.conf file for some reason.
I want to use destination variable in below condition

lookuphost:
condition = $if eq {$destination variable}{destination address /or
domain }{yes}{no}
driver = lookuphost
transport = remote_smtp
please help me
Best regards
MO