Group of people working together established firm (6)
I believe the answer is:
stable
'firm' is the definition.
(similar in meaning)
'group of people working together established' is the wordplay.
I cannot quite see how this works, but
'group' could be 'table' (table is a kind of group) and 'table' is located in the answer.
A single letter 's' remains which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for stable that I've seen before include "setting for the Nativity" , "Immutable" , "Bleats (anag)" , "Firm - building for animals" , "Products all from same place" .)