I don't think there's anyway to limit the tables available (visible), but it's
certainly possibly to prevent users from selecting from them.

You say: <<by checking what SQL role they are in.

You'll need to go back to that role and set the SELECT permissions on only the
tables that the SALES people need.

Sure, they might be able to "see" every table in MS Query, but they should only
be able to select records from tables with the appropriate SELECT permissions.
If the add a table w/o SELECT permission, the driver should return an error
like "user does not have the appropriate permsission on object <table"

The bottom line is that you can't limit the tables "showing up" in MS Query;
you'll have to control this from SQL Server.