multiple ldap-servers for kolab-saslauthd

Hi all,

while it's possible to have multiple ldap servers for redundancy in
nearly every service (postfix, imap), I wonder if this is also the case
for kolab-saslauthd.

Since it reads it's configuration from kolab.conf I think, the only
option there is

  ldap_uri =

So how to achieve to have redundant ldap servers also for authenticate
users?

Thanks and regards
Jan