If you are hosting a domain on the internet and have a host you would like to reach via an internal address instead of an external address then you can do this in UCS. Adding the entry to the GUI is an option but if importing a large zone then that is NOT an option and you will need to use udm.
To add a split horizon entry you will have to add a zone entry just like in the GUI but using udm instead.
udm dns/forward_zone create --set zone="bwweb01.bergwerk-it.de." --set a="10.3.1.103" --set nameserver="bwuniventionmaster.berg45.de."