If you hide all but the summary sheets and protect the workbook with a
password, you can then put in a auto_open macro to prompt for a password and
unhide sheets based on the response.
You would also need a auto_close macro to hide all of the sheets again for
the next user. You can get much fancier and do a custom form that uses
password characters, but that gets more involved.
In this simple version if the user hit cancel or enters an unrecognized
password no sheets will be unhidden. For added security protect the VBA
project so no one can get to the code and find the workbook password.
Something like this:
Sub Auto_Open()
x = InputBox("Enter Dept Password")
ActiveWorkbook.Unprotect Password:="password"
If x = "accounting1" Then Sheets("Sheet1").Visible = True
'ADD OTHER CONDITIONS
ActiveWorkbook.Protect Password:="password", Structure:=True, Windows:=False
End Sub
Sub Auto_Close()
ActiveWorkbook.Unprotect Password:="password"
Sheets("Sheet1").Visible = False
'ADD OTHER SHEETS
ActiveWorkbook.Protect Password:="password", Structure:=True, Windows:=False
End Sub