It's possible, but I had to do mine manually.
First create a normal network USB boot disk from Ghost Boot Wizard using one of the drivers you want.
Once that's finished, under the NET directory on the drive, create a folder for the driver you used and copy the [DRIVER].dos and protocol.ini file from the NET folder to the NET\[DRIVER] folder.
For each of the other drivers, create a NET\[DRIVER] folder and copy the [DRIVER].dos and protocol.ini files from your template directory.
At the root of the flash driver, edit autoexec.bat so it's contents are this:
@ECHO OFF
SET TZ=GHO+05:00
prompt $p$g
IF "%NET%" == "" GOTO NONET
:YESNET
ECHO Loading Network Driver...
\NET\NETBIND.com
:NONET
IF EXIST MOUSE.COM MOUSE.COM
echo Loading Ghost...
\GHOST\GHOST.EXE
Then edit config.sys so that it's in this format:
[menu]
MENUITEM=DRIVER1, DRIVER 1 NAME
MENUITEM=DRIVER2, DRIVER 2 NAME
MENUITEM=DRIVER3, DRIVER 3 NAME
MENUITEM=NONE, NONE - LOCAL ONLY
MENUCOLOR=7,0
[COMMON]
LASTDRIVE = Z
[DRIVER1]
SET NET=DRIVER1
DEVICE=\NET\protman.dos /I:\NET\DRIVER1
DEVICE=\NET\dis_pkt.dos
DEVICE=\NET\DRIVER1\DRIVER1.dos
[DRIVER2]
SET NET=DRIVER2
DEVICE=\NET\protman.dos /I:\NET\DRIVER2
DEVICE=\NET\dis_pkt.dos
DEVICE=\NET\DRIVER2\DRIVER2.dos
[DRIVER3]
SET NET=DRIVER3
DEVICE=\NET\protman.dos /I:\NET\DRIVER3
DEVICE=\NET\dis_pkt.dos
DEVICE=\NET\DRIVER3\DRIVER3.dos
[NONE]
You can have as many network drivers as you want. Just select the proper card from the menu when you boot to the flash drive. I've attached a zip file of my universal boot disk for reference