Yes, it is possible.
Just edit or delete the Assisted Install.txt file that comes with the installer.
By the way, this works for Windows too...
i know it works on win... but on Mac its in the dmg, so when you try to edit it, you get a message saying that you cant't.
1) Open Disk utility
2) Select "Convert..." from the Images menu (or click the icon)
3) Select the original DMG
4) In the Save dialog, under Image format, select "read/write"; Encryption: none.
Now you have a DMG that can be edited, like in removing stuff from it.