Joined in group in Indian river, almost died (6)

'joined in group' is the definition.
(joined as part of a gang)

'indian river almost died' is the wordplay.
'indian river' becomes 'ganges' (I've seen this before).
'almost' means to remove the last letter (most of the word but not all of it).
'died' becomes 'd'.
'ganges' with its final letter taken off is 'gange'.
'gange'+'d'='GANGED'

'in' is the link.