[exim] Trouble with condition statement

Hi!

I have this condition statement in a spam filter router which works well:
condition = "${if and {{!def:h_X-Spam-Flag:}
{!eq{$received_protocol}{spam-scanned}}} {1}{0}}"

but I also want to add a clause only to continue if the user's email address
exists in a
text file.. I have this but can't get it logically 'and'ed with the above
(or maybe's its invalid?):
${lookup{$local_part@$domain}lsearch{/etc/mail/filtered_users}}

Can anyone help piece it together? Many thanks, Andrew.