The most common and most likely answer to this crossword clue is the 7 letter word CLIQUES
I've seen this crossword clue in The Sunday Telegraph
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More clues leading to the result CLIQUES
Buddy explains!
The straight part
We know that "Exclusive groups" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case exclusive groups = cliques.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.
What does CLIQUES mean?
CLIQUES noun- A small, exclusive group of individuals, usually according to lifestyle or social status; a cabal.
- A subgraph isomorphic to a complete graph.
- A group of related web sites that link to each other, like a webring but with exclusive membership determined by the clique owner.