Group having drink before start of meal (4)
I believe the answer is:
team
'group' is the definition.
(team is a kind of group)
'drink before start of meal' is the wordplay.
'drink' becomes 'tea' (tea is a kind of drink**).
'before' says to put letters next to each other.
'start of' suggests taking the first letters.
The first letter of 'meal' is 'm'.
'tea'+'m'='TEAM'
'having' is the link.
(Other definitions for team that I've seen before include "Side; match" , "(Football) side" , "(Sports) side" , "Mate for a group of players" , "Crew" .)