I just tried this in a query - it's an inner join on 2 fields using "Or". It won't display in design view, but it works. Is there any reason not to use it?
SELECT Employees.FirstName, Employees.LastName, Customers.FirstName, Customers.LastName
FROM Employees INNER JOIN Customers ON ((Employees.FirstName = Customers.FirstName) OR (Employees.LastName = Customers.LastName));
SELECT Employees.FirstName, Employees.LastName, Customers.FirstName, Customers.LastName
FROM Employees INNER JOIN Customers ON ((Employees.FirstName = Customers.FirstName) OR (Employees.LastName = Customers.LastName));