pywinauto: how to set focus at one random window when there can show up one window from three different

I am trying to automate some application using pywinauto but there is some step that I don't know how to solve.

When I am at the main window I click "proces" buton and after this there is a possibility to open 1 window from 3 different but only 1 at a time. Please help me to solve this.

example: main window --> buton click --> 1st window (process file) or 2nd window (Your password expired, set new password) or 3rd window (this user is already logged in please kill his session and continue or break) --> process 1 of 3 windows but which will show up I don't know --> ...