How do I allow users to view grouped rows while still protecting d
 

I used the group & outline feature to take several rows and "group" them
together so that on the far left side of the sheet it has a + sign that when
selected drops down the grouped rows. I need to protect the cells in this
sheet as they are filled with formulas but when I protect the sheet it no
longer allows the viewers to view the grouped rows. How do I protect the
sheet while still allowing viewers to drop down those rows?