Gathering given drink with five abstaining (4)
I believe the answer is:
bevy
'gathering given drink' is the definition.
'bevy' can be an answer for 'gathering' (I've seen this in another clue). I'm not sure about the 'given drink' bit.
'with five abstaining' is the wordplay.
'with' means one lot of letters goes inside another.
'five' becomes 'V' (Roman numeral).
'abstaining' becomes 'bey' (I am not sure about this - if you are sure you should believe this answer much more).
'v' put into 'bey' is 'BEVY'.
(Other definitions for bevy that I've seen before include "Gaggle" , "Group of birds or girls" , "Group of e.g. girls" , "Collective noun for beauties" , "female company?" .)