If you do not want the ordinary user to see a table in your database, you can hide it in the database windows so that other users cannot select it.
Preface the table's name with the four letters 'Usys'. For example, if your table's name is ProprietaryCosts , change it to Usys ProprietaryCosts. This makes your table into a system object which Access does not display.
To see this table later, in Tools>Options, on the View tab in the Show section, put a check mark by System objects.
If we agree among ourselves not to tell the uninitiated, no one need be the wiser.