Microsoft Access Security

So I get how to connect Access to SQL Server, and I understand that the tables have to be linked, but my problem is security. If I link the tables from SQL Server into Access, then anyone who comes into the Access forms to enter data can ultimately get at the tables via the link can't they? I know that newer Access versions have no user security, but is there any way to restrict what data they see in some of the tables, or do I need to do that on the back end in SQL Server Express?