[Exim] LDAP query

Hi all,

i'm using exim with LDAP query for receiver verify of local domains.

I have this directors:

local_not_exist:
    condition = "${lookup ldap
{ldap:///c=IT?mail?sub?(&(shortname=$local_part))}{0}{1}}"
    driver = smartuser
    transport = rcpt_not_found_autoreply

local:
driver = smartuser
transport = internal_smtp

Now i would like to do like this with my relay domains (domain where i am
their backup).
Can i use "condition" in routers section?

Thank you

Riccardo