Conspire with company, upsetting dim middlemen (7)
I believe the answer is:
collude
'conspire' is the definition.
(synonyms)
'company upsetting dim middlemen' is the wordplay.
I cannot quite understand how this works, but
'company' could be 'co' (abbreviation) and 'co' is found within the answer.
This may be the basis of the clue (or it may be nonsense).
'with' is the link.
Can you help me to learn more?
(Other definitions for collude that I've seen before include "Agree in secret" , "Be in cahoots" , "Conspire fraudulently" , "Conspire to defraud" , "Plot secretly with someone to commit a crime" .)