Social group using many a blend of teas (5)
I believe the answer is:
caste
'social group' is the definition.
(I've seen this before)
'many a blend of teas' is the wordplay.
'many' becomes 'c' (C is the Roman numeral for 100).
'a blend of' indicates anagramming the letters (I've seen this in other clues).
'teas' is an anagram of 'aste'.
'c'+'aste'='CASTE'
'using' is the link.
(Other definitions for caste that I've seen before include "place in society" , "Social order" , "Hereditary Hindu social division" , "Social class in Hinduism" , "Persons with class" .)