Anytime you book a codeshare flight operated by another carrier, or any non-NZ flights on the same booking, it generates a unique PNR (passenger name record) on that airline's reservation system. However, if you book multiple airlines that share a system (like LH/LX/OS) usually all those carriers' flights will be on a single PNR.
If a travel agent books your ticket they can access all the PNR codes for any airlines in their system.