How Do I Scale a Group of Objects

Hi, I want to scale a “Group” of objects but when I scale them each object scales differently.

I have a house and have created a Dupligroup Object, but when I select all of the objects and scale the windows, walls, roof etc. don’t scale proportionately.

I thought the “lock” icons beside the Scale would lock the scale so you could scale objects proportionately, but it doesn’t seem to that.

How do I scale a Group of objects?

pg

Create an empty.
Turn on dupligroup
Type in the name of your group.
Scale the empty.
Hide the originals on another layer.