IIS 6.0 SMTP reject invalid email

I'm trying to avoid the huge numbers of NDRs that my Exchange environment is
currently processing for non-valid e-mail addresses. I am running Microsoft
IIS SMTP 6.0 relay at my inbound Internet e-mail gateway. I want to "reject"
any e-mail at the gateway if there is no valid e-mail address in my Exchange
environment. For example my e-mail address is jschmo@domain.com so e-mail
will be accepted for this address. If an e-mail is sent to jjjjj@domain.com
(which does not exist in our environment) I want to reject or drop this
inbound e-mail at the gateway. Is this something that can be accomplished
through using the LDAP routing feature for IIS SMTMP relay? If so, are there
clear instructions available on how to configure this w/ AD?