There few ways to do so.
However it is Not a simple affair if your Network and the computers were not organized ahead for such an installation, you might need to invest a time and some money to bring it to be able to so.
It worth while to go through it when you know that you would need such more Network installations on a frequent bases, but for one time installation of 4 peer to peer computers, Nah.
:sun:
P.S.
If the 4 computers can boot from CDROM, they have similar hardware, and you want them to be configured with Windows like you current computer is configured, you can save some time.
Buy a program like Acronis TrueImage and make an image of the current Computer (make sure that the computer can share the Hard Drive). Use TrueImage to make bootable recovery CD.
You can use the recovery CD to boot each new computer and install through the Network the previously produced image. You would need then to adjust Network setting and Activate Windows, and any other program that need activation.