I successfully created a multibootable USB using WinSetupFromUSB, allowing me to boot into an ISO for MS-DOS 6.22 and installer ISOs for Windows 7 32- and 64-Bit from a single bootable USB. However, while the Windows 7 ISOs are both accessible from the Windows Boot Manager (bootmgr), MS-DOS requires grub4dos to be loaded.
This means that my bootable USB is split into two separate boot menus; the grub4dos menu, which is initially booted into and contains the menu entry for booting into DOS 6.22, as well as another two (first and second half of Windows 7 installers) for booting into bootmgr, from where both the Windows 7 entries can be found.
I don't like this way of doing things, and I'd really like to unify all four entries into one single menu under bootmgr. Is this at all possible?