Here, I whipped something up, modify as you like. It could be much shorter, but you get the idea.
Insert a combobox (on a master sheet, mine is named "control"), assign it a list and then place this macro in the visual basic. Group as you like, be sure one sheet is always visible and leave a case to show all.
Sub DropDown1_Change()
With ActiveSheet.Shapes(Application.Caller)
Select Case .ControlFormat.ListIndex
Case 1
Sheets("Control").Visible = xlSheetVisible
Sheet2.Visible = xlSheetVisible
Sheet3.Visible = xlSheetVisible
Sheet4.Visible = xlSheetHidden
Sheet5.Visible = xlSheetHidden
Sheet6.Visible = xlSheetHidden
Sheet7.Visible = xlSheetHidden
Sheet8.Visible = xlSheetHidden
Sheet9.Visible = xlSheetHidden
Sheet10.Visible = xlSheetHidden
Sheet11.Visible = xlSheetHidden
Case 2
Sheets("Control").Visible = xlSheetVisible
Sheet2.Visible = xlSheetHidden
Sheet3.Visible = xlSheetHidden
Sheet4.Visible = xlSheetVisible
Sheet5.Visible = xlSheetVisible
Sheet6.Visible = xlSheetHidden
Sheet7.Visible = xlSheetHidden
Sheet8.Visible = xlSheetHidden
Sheet9.Visible = xlSheetHidden
Sheet10.Visible = xlSheetHidden
Sheet11.Visible = xlSheetHidden
Case 3
Sheets("Control").Visible = xlSheetVisible
Sheet2.Visible = xlSheetHidden
Sheet3.Visible = xlSheetHidden
Sheet4.Visible = xlSheetHidden
Sheet5.Visible = xlSheetHidden
Sheet6.Visible = xlSheetVisible
Sheet7.Visible = xlSheetVisible
Sheet8.Visible = xlSheetHidden
Sheet9.Visible = xlSheetHidden
Sheet10.Visible = xlSheetHidden
Sheet11.Visible = xlSheetHidden
Case 4
Sheets("Control").Visible = xlSheetVisible
Sheet2.Visible = xlSheetHidden
Sheet3.Visible = xlSheetHidden
Sheet4.Visible = xlSheetHidden
Sheet5.Visible = xlSheetHidden
Sheet6.Visible = xlSheetHidden
Sheet7.Visible = xlSheetHidden
Sheet8.Visible = xlSheetVisible
Sheet9.Visible = xlSheetVisible
Sheet10.Visible = xlSheetHidden
Sheet11.Visible = xlSheetHidden
Case 5
Sheets("Control").Visible = xlSheetVisible
Sheet2.Visible = xlSheetHidden
Sheet3.Visible = xlSheetHidden
Sheet4.Visible = xlSheetHidden
Sheet5.Visible = xlSheetHidden
Sheet6.Visible = xlSheetHidden
Sheet7.Visible = xlSheetHidden
Sheet8.Visible = xlSheetHidden
Sheet9.Visible = xlSheetHidden
Sheet10.Visible = xlSheetVisible
Sheet11.Visible = xlSheetVisible
Case 6
For Each ws In Worksheets
ws.Visible = xlSheetVisible
Next
End Select
End With
End Sub