Process GPP before Software Install in same GPO

Hi

I want to process some registry changes by GPP before the software install msi runs.  Ideally I'd like all of this in the same GPO, but can't see a way to change order, or by default does the polices process before the software installs?

If there isn't a way to do it in one GPO, I'll have to seperate the GPP and the software install and then use ordering.