How to copy forum structure Advanced Forum?
What you should do is something like an Install Profile: https://drupal.org/developing/distributions

You can create Install Profiles from exiting sites with:
https://drupal.org/project/profiler
https://drupal.org/project/profiler_builder

What I would do is make the first site exactly how you want it and then turn that into a Install Profile.

An easier way to do this if you have AEgir is to just clone your first site and then keep it as a template to clone others.