Multiboot, choice in Windows - how?

Question

Active Directory

Given: a virtual machine, a 480 gig disk image is divided into 16 sections of 30 gig each (for example).
On each of the sections - Windows.
Question: how to send a virtual machine to reboot, choose a partition from which to boot?
I clarify that access to the virtual machine is only via RDP and at the time of boot (as is usually done on a physical machine) it is impossible to make a choice. You must specify the desired option before rebooting.
By the way, I am also considering network booting - it is possible that you need to boot two or more virtual machines from a certain set of images.
I plan to use XCP-ng as a hypervisor
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The explanation is available a farm of domain controllers, and these images of Windows are machines with RSAT installed for these domains. In other words, usually at any given time, an image for only one domain is loaded in the virtual machine. And if you cling to this virtual machine remotely via RDP, then you will not be able to select the desired image at the time of loading. In short, you need to specify in which image to boot BEFORE rebooting. There is also an option to use to boot the PXE image.