[exim] question of string expansion and condition=

Hi

I am trying to have a look up dependent on the $primary_hostname in a file via the condition restriction on a router.

What I want is that if the $primary_hostname is in the file with no further information then defaults apply, else if there is some information then that will be used.

But the router will not run if the look up returns a blank if we have a file like

exim-box1.localdomain:
exim-box2:localdomain: data...data

My condition is

FILENAME=/abc/def
Condition = ${lookup{$primary_hostname}lsearch{FILENAME}}

For exim-box1.localdomain the router does not run. It does for exim-box2.localdomain. Trying ${if has lead to no joy. Can you please assist?
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