How to rotate world volume?

I have a working simulation. Then I replaced the standard Geant4 geometry with a gdml version, because it is more detailed etc… Everything works fine, except now the objects of the gdml file are oriented in a different way than the original geometry. This causes my simulation to not work correctly. I could of course just create the gdml version with a different orientation matching the original one, but for reasons, I don’t want to do that. There are 100+ objects (physical volumes) in the gdml geometry. Can I rotate them all at once? If so, how? Apparently, I am not allowed to rotate the world volume. I tried that.

Thank you in advance!