Power behind cooker to sort out in advance (10)

I believe the answer is:

prearrange

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'to sort out in advance' is the definition.
I can't tell whether this defines the answer.

'power behind cooker' is the wordplay.
'power' becomes 'p' (symbol in physics).
'behind' becomes 'rear' (both can mean one's bottom).
'cooker' becomes 'range' (I've seen this in other clues).
'p'+'rear'+'range'='PREARRANGE'

Can you help me to learn more?

(Other definitions for prearrange that I've seen before include "set up in advance" , "Agree in advance" , "Decide in advance" .)

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