They will spend their time together (9)

I believe the answer is:

cellmates

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'together' is the definition.
I know nothing about this answer so I can't tell whether it can be defined by this definition.

'they will spend their time' is the wordplay.
I cannot really see how this works, but
'will' could be 'll' and 'll' is found in the answer.
'time' could be 't' (abbreviation) and 't' is present 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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