Again if I am way off what you were asking please disregard. I grabbed one of my lone star sample blocks that I used as a teaching sample. This one because I knew I wasn't making an store quilt I just made my set in triangles and squares larger to give it a border. But I think you can see where I was going with my previous post.
I laid some fabric scraps down in what would be a half square triangle in the corner and then the two rectangles would have a half square sewn on the end to complete the unit. These would attach to the smaller squares. Then when the other blocks are sewn together those corner units create a secondary star.
I hope this helps in some way.