Log onto the publisher, run the DC Directory bulk export tool. Select "Mode = Export" and then decide what info you want to export by specifying the context in the "Root DN" field. If all you need is to have their names and phone numbers in the directory on another server then you can stick to /O=cisco.com/OU=Users. If you want the whole thing, go with /O=cisco.com. Transfer the flat file(s) that is output to the other server and then run the DC Directory bulk import tool with that file.
If all you want to do is make users on other clusters searchable from the IP Phone directory, you can also create a search service with the ldapsearch service in the IP Phone Services SDK. That would save you from possibly mucking up the directory as well as considerable administrative effort since MACs to the users in the original directory will not get replicated to the directories on other servers that aren't on the same cluster.
