Working group, we hear, for vineyard (3)
I believe the answer is:
cru
'vineyard' is the definition.
(I've seen this before)
'working group we hear' is the wordplay.
'working group' becomes 'crew' (I've seen this in another clue).
'we hear' indicates a 'sounds like' (homophone) clue.
'crew' sounds like 'CRU'.
'for' acts as a link.
(Other definitions for cru that I've seen before include "French vineyard or group" , "Vineyard or group of them in France" , "Source of alcohol" , "Growth place of a French wine" , "(Quality) vineyard; sounds like ship's men" .)