How to put XP, Vista & 7 Installation ISO into USB

I have successful put the Windows installation ISO (XP, Vista & Windows 7) into USB Flash Drive or External Hard Disk and it works very fine.

However, each installation ISO is limited to 1 USB Storage.

Is there a way to put 3 Windows Installation ISO into single USB External Hard Disk?
I can boot from the USB Hard Disk and a menu came out, so that I can choose which OS (XP, Vista or 7) to be install.

You should be able to do that if you partition the hard drive correctly. Use something like Partition Wizard to partition the hard drive into however many partitions you require.

Now follow the instructions as you would have before.

There are several ways of going about it.

1) Use MagicIso, it has a multi image boot editor. Heres a tutorial.

Using MagicISO to make multiple bootable image file

2) Use the MS deployment kit and WAIK.

Creating a Multi-OS Installation USB Key - The World According to Mitch

3) This way using a preexisting AIO disk.

Can I boot multiple Win Os's from a USB HD (to install only)?

Also, if you are into bootable usbs, check out these 2 sites. They have tonnes of good info.

Boot Land

www.msfn.org

Many thanks for the tips. I will go and check it out for the info.
Thanks again, dude.