Separate complaints department (9,4)

I believe the answer is:

isolation ward

I'm a little stuck... Click here to teach me more about this clue!

'separate complaints' is the definition.
I know nothing about this answer so I can't judge whether this works.

'department' is the wordplay.
I cannot really understand how this works, but
'department' could be 'war' (War Department is an example) and 'war' is located in the answer.
This explanation may well be incorrect...

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I've seen this clue in The Globe and Mail.

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