Using multiple realms with saslauthd/ldap

[John Newbigin]

Hi. I have a working ldap/sasl/saslauthd/ldap set up with openldap using 
passthrough authentication as per 
http://www.openldap.org/doc/admin24/security.html#Pass-Through%20authentication

The problem is that I would like to use the realm to specify which 
server to authenticate against.

The ldap settings in /etc/saslauthd.conf are quite different for each 
server (ie. it is more than the filter which needs to be changed).

Is there a way which a per realm configuration can be used? Either 
directly with sasl or with saslauthd?

I am currently using the RHEL 4 version of sasl (cyrus-sasl-2.1.19-14) 
but I could upgrade if that was required.

Any help or pointers would be greatly appreciated.

Thanks

John.