[exim] How to rewrite ${filter ...} expressions for older ex…

I am burdened with an exim.conf that has the following two lines in it:

address_data = ${filter {<\n
LDAP_UID_QUERY}{eq{LDAP_GROUP_QUERY}{LDAP_MAIL_GROUP}}}

condition = ${if >{${strlen:${filter {<\n
LDAP_UID_QUERY}{eq{LDAP_GROUP_QUERY}{LDAP_MAIL_GROUP}}}} }{0}}

Exim 4.63 (as supported by CentOS 5) does not understand ${filter ...}.
Does anyone have any hints on how to reformulate this without using
filter? (And no, I don't want to upgrade exim.)

Thanks,
Michael