Is there some kind of table-level replication in PostgreSQL?
I finally managed to find a solution that works so far. I installed plpython procedural language module along with the psycopg2 module, wrote a FUNCTION and created two TRIGGERs, one for INSERT and one for DELETE (I won't have any UPDATE events).

The function code would be something like this:

CREATE OR REPLACE FUNCTION synchronize()
RETURNS trigger AS
$$
    import psycopg2

    conn = psycopg2.connect("host=... dbname=... user=... password=...")
    cur = conn.cursor()

    # If inserting...
    if TD['event'] == 'INSERT':
      cur.execute(...)

    # If deleting...
    if TD['event'] == 'DELETE':
      cur.execute(...)

    conn.commit()
    cur.close()
    conn.close()
$$
LANGUAGE 'plpython2u' VOLATILE;


Then, I defined both triggers:

CREATE TRIGGER replica_insert
AFTER INSERT ON users
FOR EACH ROW
EXECUTE PROCEDURE synchronize();

CREATE TRIGGER replica_delete
BEFORE DELETE ON users
FOR EACH ROW
EXECUTE PROCEDURE synchronize();


Maybe over-complicated, or patchy, but right now this is the easiest way I found how to do it. If someone improves it or has an alternative (preferably native) way to do it, I'll be glad to change the accepted answer.