How and where to write a search filter script??????

[Kristina <kristina@fsas.fujitsu.co.jp>]

I am referring to the following document to write the following user entries
for intranet email routing.
http://www.ietf.org/internet-drafts/draft-lachman-laser-ldap-mail-routing-01
.txt

I have compiled Sendmail 8.9.3 with LDAP support on the mail hub,
however I do notknow how to write the search filter (not command, script form)
for intranet email routing of incoming mail.

Here are the details:

Each user's entry looks like this****************

dn: cn=name, o=organization, c=JP
objectClass: top
objectClass: person
objectClass: organizationalPerson
objectClass: inetLocalMailRecipient
cn: root
sn: Mpoyi-Mpoyi
cn: Kristina
mail: name@domain.co.jp
mailLocalAddress: name@domain.co.jp
mailHost: host.domain.co.jp
mailRoutingAddress:name@domain.co.jp

.....and so I want to write a search filter for sendmail to query ldap on
where to route email.
Sendmail should lookup the ldap server for a "mail" or "mailLocalAddress" en
try
in the 
database for the for the mail to route and if it there is a match, routed the
mail to the host
defined by the  "mailHost" entry with the "mailRoutingAddress".


The above mentioned document describes exactly what I want to do "email rout
ing
wise" 
but not on HOW or WHERE to configure the search filter to do so.  

I am in real need of help!
Thanks in advance,
Kristina