Looking on my system it appears that the guest operating system running on the VM handles memory paging. Thinking about it this makes sense because the guest OS will be better able to determine how data in memory is being used to minimize the performance impact of paging. It seems the easiest solution is to assign each VM a VHDx that is located on the new drives and configure each guest OS to use that virtual drive for the page file. RAM usage will probably stay very high since it is better to use up all the RAM before aggressively moving stuff to page files. If you really want RAM usage to show a lower number you would probably have to set a lower maximum amount of RAM in the hyper-v setting for each VM to force the guest operating system to make more use of the page file.
This all assumes your using dynamic memory for the VMs. Also see https://free.blessedness.top/en-us/previous-versions/windows/it-pro/windows-server-2008-R2-and-2008/ff817651(v=ws.10)