The most common and most likely answer to this crossword clue is the 10 letter word RECIPIENTS
I've seen this crossword clue in The Sunday Telegraph
R
E
C
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P
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Buddy explains!

The straight part
We know that "beneficiaries" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case beneficiaries = recipients.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 RECIPIENTS mean?
RECIPIENTS noun- One who receives.
- An individual receiving donor organs or tissues.
- The portion of an alembic or other still in which the distilled liquid is collected.