multiple LDAP servers for multiple domain?

[tiger2000]

Dear All,

i've read the zimbra (OS) Multi-Server installation guide , and it looks like we can have multiple LDAP replica servers to share loads. but i'm curious, when customer has several domains which locates in different countries, how could we implement zimbra for this need? can we setup ldap replica server in each country for local query and of course, each country is running different email domain.

to be more specific :

country1 : @country1.com (head office) , master LDAP, mailbox, mta
country2 : @country2.com, ldap replica, mailbox, mta
country3 : @country3.com, ldap replica, mailbox, mta

by the way, is there anything we should consider in this kind of deployment?
up-side, down-side?

Thanks.