Colleagues filling shop, possibly (5)

I believe the answer is:

oppos

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'colleagues' is the definition.
(oppo can mean a colleague or associate)

'filling shop possibly' is the wordplay.
'OPPOS' is hidden in amongst the letters.
However, I am uncertain how the hidden word is indicated.

Can you help me to learn more?

(Other definitions for oppos that I've seen before include "Partners" , "friends" , "One's counterparts" , "colleagues elsewhere" .)

I've seen this clue in The Times.

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