CREATE RULE with WHERE clause

Hello,

I need to create a rule, but I need that it have a WHERE clause, how bellow:

CREATE RULE rule_role_sul AS
ON SELECT TO t1 WHERE roles = 'role_sul'
DO INSTEAD
SELECT field1, field2 FROM t2;

CREATE RULE rule_role_sul AS
ON SELECT TO t1 WHERE roles = 'role_norte'
DO INSTEAD
SELECT field3, field4 FROM t2;

Someone knows how can I do it?

I appreciate any help

Thanks