I don't believe the LDAP, or AXL, import would allow you to do that. If not doing it the way you're doing it, not sure if there might be a way through the APIs to get that info directly from the LDAP server and push that into CUC, but you'd need to build the app/script to do that, assuming that's possible.
I don't deal with the APIs, so I'm just thinking out loud here.
HTH
java
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