Prevent Saving Certain Worksheets On Save As

In my program I have prevented the user from saving the Workbook with the following code

Private Sub Workbook_BeforeSave(ByVal SaveAsUI As Boolean, Cancel As Boolean)
Dim p As String
Cancel = True
Do While Cancel = True
p = InputBox("Enter password to save file:", "Password Required To Save", "")
If p = "Enter Password Here" Then
Cancel = False
Else
yn = MsgBox("Wrong password. Try again?", vbYesNo, "Invalid Password")
If yn = vbNo Then
Exit Sub
End If
End If
Loop
End Sub

I also need to prevent the user, when they use the save as, from saving certain worksheets. Ex: There are 6 worksheets in the workbook. I only want them to be able to save the first three. Issues: One of the workbooks that I want to allow them to change has a tab name that changes frequently.