How do I put the 4 install discs on one USB drive for setup

[StarGehzer]

I'm having trouble explaining what I want to do. Sorry.
I have the set of original X220 setup discs. I want to do a fresh install from a USB flashdrive.
I know how to make the flashdrive bootable & install the first ISO, but what do I do with the other discs?
I want to copy them to the same flashdrive & have the install flow smoothly from disc 1 to disc 4.
Do I need to put discs 2-4 in folders with a special name so that the setup will find them or is there another trick to it?

Note: There are actually 5 ISO files for the X220, but I'm only intending to use the first 4.
Also, instead of the Disc 1 from the X220 setup, I'll be using the Disc 1 for the T420s as it has Win7 SP1, then I'll use the 3 x220 driver discs.

[dr_st]

I don't have firsthand experience, but my gut feeling is telling me that your chances for success would be if you simply dumped all the files and folders from all four disks into the same relative location on the USB flash drive.

Overall, I wouldn't suggest you go this way anyways. I would just install a fresh Win7 SP1, then download all the drivers manually or using System Update. This gives you control over what you install and you can avoid some of the useless bloat (or just things you don't want).