The most common and most likely answer to this crossword clue is the 6 letter word SET-UP
I've seen this crossword clue in Independent
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More clues leading to the result SET-UP
Buddy explains!

The straight part
We know that "organisation" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case organisation = set-up.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
Crossword Answer definitions
SET-UP noun- Equipment designed for a particular purpose; an apparatus.
- The fashion in which something is organized or arranged.
- A situation orchestrated to frame someone; a covert effort to place the blame on somebody.
- An installer.
- (operations) The process of arranging resources for performing a specific operation, as a run of a particular product.
- The tendency of persistent wind to produce higher water levels at the downwind shore of a body of water and lower at the upwind shore.