Well, the MW Dictionary of English Usage is clear on this matter:
"Who also refers to words for entities that consist of people" (p. 896).
The authors of the Dictionary also mention that in the past which was also used of persons but now "is usually limited to things" [emphasis mine - Alex B.].
However, if you treat an "entity that consists of people" as one unit, then which is more common than who, cf.
The committee, who are hoping to announce important changes, ....
The committee, which is elected at the annual meeting, ....
(examples from Swan 2005).
UPDATE: Here are some examples I've been able to find (British English)
It is exactly why people have been occupying St Paul’s to protest against the behaviour of the City elite and the government who is turning a blind eye. (The Times, 2011)
The result was ignored by the Government, who locked up Ms Suu Kyi and her lieutenants for decades. (The Times, 2012)
The only people with any authority in this matter are the Scottish government who have jurisdiction on the matter ...." (The Times, 2011)
'"The Government, which had not adequately consulted on the plans, he said, was 'mistaken' if it thought the changes would be cost-neutral".' (The Times, 2012)
The Lebanese Government, which is backed by Damascus, has adopted a policy of disassociation ...." (The Times, 2012)