>Is there a way to visually set up relations between two tables in the database
>designer? I have two tables containing company id fields and would like to set
>up a relationship for them.

In the database designer, you need to create the link between indexes, rather than the field names. One of the indexes must be a Primary Key.

Bear in mind that this will not automatically link them, but it will support Referential Integrity (can't delete a company that's still being referred to, frex), and the Form Designer will also pick up on them.