I am trying to make a toilet paper like object in blender. 
I have cut a hole in cylinder with boolean modifier. The problem is when I scale this object in Unity the hole gets bigger as we expect. I need to set this object so that I can scale only the outside of the cylinder. Can I restrict which parts should be scaled? Even when this is possible I don't know whether Unity will do the same thing. I'm new in Blender. Thanks for help!