Can the last of you set up a group? (4)
I believe the answer is:
unit
'a group?' is the definition.
(unit is a kind of group)
'can the last of you set up' is the wordplay.
'can' becomes 'tin' ('tin' can be a synonym of 'can').
'the last of' says to take the final letters.
'set up' says the letters should be written backwards.
The final letter of 'you' is 'u'.
'tin'+'u'='tinu'
'tinu' in reverse letter order is 'UNIT'.
(Other definitions for unit that I've seen before include "army group" , "Entity, system; component group" , "Single whole as part of a larger whole" , "Building block - small military force" , "Single piece - kitchen cabinet" .)