XBOOT is a tool for Windows PC which can be used to create Multiboot USB/ISO. If you have multiple boot CDs or bootable USB images and would like to store them all on one CD or USB and choose which to boot into, this tool is precisely what you are looking for. Xboot also included a built-in QEMU emulator which enables you to boot ISO and Operating Systems on your PC in a virtual environment.
All the applications are required to have the ISO image file of the bootable media such as Linux Live CD, Hiren Boot Disk, Antivirus Rescue Disk, and the like. You do not need a different USB drive for each type of disk, Xboot will create a multi-boot USB drive using the various ISO drives available. You have to just drag and drop the various ISO files to the application interface and click on the Create USB button and let the application perform the magic of creating a multi-boot USB drive.