Alternative to INTERSECT

Hi all. I have the following schema:

CREATE TABLE test (   id integer NOT NULL,   field character varying NOT NULL,   value character varying NOT NULL
);

ALTER TABLE ONLY test   ADD CONSTRAINT test_id_key UNIQUE (id, field, value);

CREATE INDEX test_like_idx ON test USING btree (id, field, value 
varchar_pattern_ops);

Using INTERSECT I want to retrieve the rows matching (pseudo-code) "firstname 
LIKE ('andrea%' OR 'jose%') AND lastname LIKE 'kro%'"

on=> SELECT t.id from test t WHERE t.field = 'firstname' AND t.value 
LIKE 'andrea%'
INTERSECT SELECT t.id FROM test t WHERE t.field = 'firstname' AND t.value 
LIKE 'jose%'
INTERSECT SELECT t.id FROM test t WHERE t.field = 'lastname'  AND t.value 
LIKE 'kro%';id
---- 1
(1 row)

Is there a way to make this more efficient with another construct, or 
INTERSECT the only way to accomplish the desired result?

--
Andreas Joseph Krogh