On formal ball gowns I've tried on, I noticed companies have added a back panel to the inside of the dresses that are sewn on one side and have hook and eye closures on the other side and then there are loops on each side back that you run a ribbon through to lace over the panel.
Sorry for the bad artwork!Of course, your loops won't look like someone had to many drinks!!
You could make the inside panel the same color as the dress. I just have it a different color to illustrate what I mean.
If you have a zipper, you can remove it and just leave the seam allowances turned under when attaching the loops for the ribbon. The loops and ribbon can be from the same fabric or from contrasting fabric if you make a contrasting panel or even from satin ribbon.