In 3DSMax (GMax is a dumbed down version of 3DSMax) I would just apply an Unwrap modifier to the mesh and fix the distortions, however I would need to know which parts go to which map. So, I'd just detach the parts where the distortions are into a separate object, fix them and reattach them. But I can't be more of help, it's been years since I last saw GMax...
For exporting the unwraps, try the attachment, but I cannot guarantee it will work with GMax since it's written for 3DSMax.