How to MBR-boot to Ventoy from grub2

[Steve2926]

If ventoy grub2 boot code is not installed to the USB drive, how can I boot to Ventoy from another grub2 menu as there is no Ventoy core.img file present?

i.e.

1. Prepare USB drive with partition 1 and partition 2
   
2. standard grub2 is installed on USB drive
   
3. copy ventoy files from a ventoy USB drive to partition 2
   
4. MBR-boot to standard grub2 menu
   
5. Choose a grub2 menu entry to boot to Ventoy MBR grub2 on the second partition
   

if I get core.img.xz and extract core.img and use
multiboot (hd0,2)/ventoy/core.img
it hangs.