Gang edges on success finding control (7)

I believe the answer is:

possess

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'control' is the definition.
(thesaurus)

'gang edges on success' is the wordplay.
'gang' becomes 'posse' (I've seen this before).
'edges on success' becomes 'ss' (I can't explain this - if you can you should believe this answer much more).
'posse'+'ss'='POSSESS'

'finding' is the link.

Can you help me to learn more?

(Other definitions for possess that I've seen before include "Have as one's own" , "influence" , "Have ownership of" , "Have and hold" , "Own, keep" .)

I've seen this clue in The Telegraph.

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