In a situation like this, once I find that one address is not enough, I allow for 1 to many by adding another table. In this case, it is something like ORGANIZATION_ADDRESS. This table just has columns like organization_id and address_id and type. Type can just be a string like 'primary' and 'registered'. You could add another table ADDRESS_TYPE and then have a type_id rather than a type, but this usually seems a bit over the top.