Silent install on Windows for all users

We have automated most of the installation of new versions of IDEA 4.0 using the install.properties file. There is only one thing missing. We are in a Windows environment and I would like the "Program Group" for IDEA to be for "All Users". It is possible to select this using the normal installer. Does anybody know how to do it with a silent install? I've searched through the ZeroG user manual referenced in the install.properties file, without finding an answer.