Domino Directory Assistance and LDAP

How to configure domino directory assistance so it searches in two different ldaps servers?

In the “Hostname” for the remote LDAP directory server I specific: ldap1.artear.com, ldap2.artear.com

But it does not find the user in first ldap, does not continue search in the other.

I need two ldap active-active, because they have different users for authentication in the same nsf and domain.

Any Ideas??

Thanks.