Software Deployment

As most people will know Microsoft have moved the goal posts once again for the Office 2007 automated insallation routine, insisting that you either create a customised .MSP file or configure the appropriate config.xml file. The issue I'm having at the moment is calling the setup.exe routine from within a wrapper MSI file. Digging into the errors a little the setup routine reports error 1618; an installation is already in progress, my question is;
Is there any way to suspend an MSI installation to start and complete another one in order to get around this error message?
I'm sure it's possible because MSI files can handle nested installs, therefore they must send a command to the Windows Installer database that either puts it in none exclusive mode so that more than one installation can occur or suspends one install and then kicks off another.
Any help on this would be gratefully received.

P.S. The reason why I have to use a wrapper MSI file is to ensure that corporate settings are installed with each software package that we produce.