The most common and most likely answer to this crossword clue is the 6 letter word SUBSET
I've seen this crossword clue in The Guardian
S
U
B
S
E
T
More clues leading to the result SUBSET
- Part of group setting British Standards in animal fat
- Not all the members having payment ready
- Busts arranged round centre of belvedere, part of larger group together
- Naval craft prepared? Only a section
- Warship went down, part of larger group
- A smaller group of alien vessels overhead
- Mathematically four bishops perhaps on board with Captain Nemo?
- Smaller group of ships, maybe those that go underwater?
Buddy explains!

The straight part
We know that "part of larger group" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case part of larger group = subset.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 SUBSET mean?
SUBSET noun- (of a set S) A set A such that every element of A is also an element of S.
- A group of things or people, all of which are in a specified larger group.
- To take a subset of.
- To extract only the portions of (a font) that are needed to display a particular document.