That's a shame - but, healthier...

Another option might be to assign the rolled-over but unjoined hem to the soft decorated group. I can't remember if I've done this or not, but it's worth a try anyway. It should force the simulator to retain the shape of the hem relative to the underlying cloth. If you assign the hem to a different material zone, it makes it easy to experiment with settings because all the vertices you want to use can be selected in one go by using the "add material" button in the group editor. Then you can try things like alternate dynamic groups as well, if you want.