Yes it's possible. I did that many many years ago. But can't remember what I used back then.

You probably need to use a boot manager like Plop or one of the many alternatives.

Ryccardo wrote on 2022-11-21, 22:10:

I have an utility disk which I often forget to remove before rebooting, so I wondered: does a program exist that will load and run the MBR off another disk (bonus points if said disk is selectable, but drive 80 only is fine too)?

This seems too obvious to not exist but I'm having trouble finding it...

Here is a hint:

C:\GRUB4DOS\GRUB.EXE --config-file="root (hd0,0);chainloader +1"