remove some rows from resultset

Hi,

I have the following table:
org_id | contract_name | org_specific_rule | count
----------+------------------+-------------------+-------
smpj28p2 | Group 123 | f | 3
smpj28p2 | Group 2 | f | 3
smpj28p2 | Group 2 | t | 9
smpj28p2 | Group 1 | f | 1
w37mtn4r | Group 123 | f | 26
w37mtn4r | Group 2 | f | 56
w37mtn4r | Group 1 | f | 55

Based on org_specific_rule and (org_id, contract_name) I need to transform this:
smpj28p2 | Group 2 | f | 3
smpj28p2 | Group 2 | t | 9

to
smpj28p2 | Group 2 | 9

in other words:
- if org_specific_rule = t then update "count" value in row where
org_specific_rule = f to value from this row (3 was updated to 9)
- remove org_specific_rule column

I have query which does everything but I have mixed feelings about it:
select
b1.org_id, b1.contract_name, coalesce(b2.count, b1.count) as count
from (select * from billing where org_specific_rule = false) as b1
left join billing b2 on
b1.org_id = b2.org_id
and b1.contract_name = b2.contract_name
and b2.org_specific_rule = true
order by 1,2;

org_id | contract_name | count
----------+------------------+----------
smpj28p2 | Group 123 | 3
smpj28p2 | Group 2 | 9
smpj28p2 | Group 1 | 1
w37mtn4r | Group 123 | 26
w37mtn4r | Group 2 | 56
w37mtn4r | Group 1 | 55

Any ideas?

--
Ondrej Ivanic
(ondrej(dot)ivanic(at)gmail(dot)com)