Postgres control flow--multiple return values - postgresql

Question

I have a bunch of queries on a business database with addresses and I often want to reclassify those as either inside or outside a given (known) area.
The SELECT CASE construct is great for this purpose, but I have often been in a situation where I want more than one return value based on the same condition tested for. For example, if the business is in a certain area, I classify it as "inside", but I may also by the same token, preferably in the same CASE block, set another value or flag, differently weigh the observation, and so on conditional on the CASE criteria being true.
What is the best/easiest way to leverage long condition statements and get multiple return values at the same time? Is that the domain of plpgsql only?
EDIT: added mock data, below. This does the categorization, but if I wanted to weigh employment for each establishment, I would need a separate CASE block, with the same critieria. That is what I am trying to get around.
SELECT
City, CASE WHEN City =ANY (ARRAY['San Francisco', 'San Mateo','Oakland','Marin','Santa Clara'])
THEN City ELSE 'outside'::text END as area,EstabEmployees
FROM (VALUES
('San Francisco', 14),
('San Mateo', 23),
('San Mateo', 3),
('San Francisco', 34),
('Visalia', 65),
('Juneau', 23),
('Mendocino', 5),
('Santa Clara', 1),
('Los Angeles', 56),
('San Mateo', 11),
('Los Angeles', 30),
('Marin', 33),
('Oakland', 14),
('Oakland', 2)
) AS t (City, EstabEmployees)
;

Answer 1

The easiest way to do this is to leverage another table or two defining the relationship.
See: http://sqlfiddle.com/#!1/ef0bb/6
To preserve for future use, here's the "Schema" for sqlfiddle (which I'm using a combination of DDL and DML)
create table metros(
id serial primary key,
name varchar(100),
data varchar (100)
);
create table metromappings (
id serial primary key,
metroid int references metros(id),
cityname varchar(100) not null
);
insert into metros(name) values ('San Francisco Area');
insert into metromappings(metroid,cityname)
select currval(pg_get_serial_sequence('metros', 'id')), name
from (values ('San Francisco'),
('San Mateo'),
('Oakland'),
('Marin'),
('Santa Clara')) as t(name);
And here's my introduction of how to use it:
select
case when m.id IS NULL THEN 'outside::' ELSE t.City END AS area,EstabEmployees
from
(metros m inner join metromappings mm
on m.id = mm.metroid and m.name =ANY (ARRAY['San Francisco Area1'])) -- add more stuff here
full outer join
(VALUES
('San Francisco', 14),
('San Mateo', 23),
('San Mateo', 3),
('San Francisco', 34),
('Visalia', 65),
('Juneau', 23),
('Mendocino', 5),
('Santa Clara', 1),
('Los Angeles', 56),
('San Mateo', 11),
('Los Angeles', 30),
('Marin', 33),
('Oakland', 14),
('Oakland', 2)
) AS t (City, EstabEmployees) on t.City = mm.cityname
order by area, EstabEmployees;
Please note, you might want to do some clustering/unique indexing on metroid,cityname, if only to remove the possibility of adding the same city to the same area twice (or just define the pair as the key and set up the id as some unique index; I'm not sure which is best).