If you're using QV11 you can use alternate states. You can add alternate states on the General tab of the document properties window. Once you done that you can assign the state to a sheet on the General tab of the sheet properties window. You need only one alternate state for the 4th sheet. The other sheets can use the default alternate state.
If you don't have QV11 than you can try using bookmarks in combination with OnActivate and OnLeave sheet triggers to save and restore selections when leaving/revisiting a sheet.