auto provision against AD domain (using LDAP), multiple LDAP servers to poll per dom?

[BloodyIron]

I'm setting up a new environment that will have a PDC and BDC, effectively a fail-over domain environment. Now, I'm making great progress with getting provisioning on Zimbra automatically. However, I cannot yet find a way to make a domain defined on the Zimbra server zmprov against multiple LDAP sources.
zmprov md domain.local zimbraAutoProvLdapURL "ldap://192.168.0.100:389"
That works against my PDC, but the point of the fail-over system is self-evident. I am unsure how to get zmprov to accept multiple LDAP URLs, and the documentation doesn't suggest how to do such so far as I can tell.
Thoughts?