Is the .pkg installation order within an .mpkg deterministic?

I've created an .mpkg package bundle for Mac OS X from a number of .pkg packages. In the post-flight script of one of the .pkg packages, I want to perform an action which depends on another one of the .pkg packages already being installed. Can I guarantee that the .pkg packages will be installed in the same order that I ordered them in PackageMaker?

Based on my own further investigation, it would seem that:

• all pre-flight scripts are run, then all packages are extracted, then all post-flight scripts are run; and
• the order in which the individual scripts are run is not deterministic.