Bruce, Christopher, Brett and Peggy in the grounds? (4)

I believe the answer is:

lees

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'grounds?' is the definition.
(I've seen this before)

I cannot understand how the rest of the clue works.

(Other definitions for lees that I've seen before include "Wine at bottom of glass" , "Sediment from wine or beer production" , "Sediment that settles at the bottom of liquid" , "Sediment that settles at the bottom of wine" , "Wine dregs" .)

I've seen this clue in the Sydney Morning Herald.

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