Retain attractive pupils for PE group (4-3,5)

I believe the answer is:

keep-fit class

'pe group' is the definition.
(physical exercise class)

'retain attractive pupils' is the wordplay.
'retain' becomes 'keep' (keeping is a kind of retaining).
'attractive' becomes 'fit' (I've seen this before).
'pupils' becomes 'class' (I've seen this before).
'keep'+'fit'+'class'='KEEP FIT CLASS'

'for' is the link.

I've seen this clue in The Guardian.

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