The most common and most likely answer to this crossword clue is the 8 letter word CONTACTS
I've seen this crossword clue in The Times
C
O
N
T
A
C
T
S
More clues leading to the result CONTACTS
Buddy explains!

The straight part
We know that "Those we know" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case those we know = contacts.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 CONTACTS mean?
CONTACTS noun- The act of touching physically; being in close association.
- The establishment of communication (with).
- A nodule designed to connect a device with something else.
- Someone with whom one is in communication.
- A contact lens.
- A device designed for repetitive connections.
- (by ellipsis) Contact juggling.
- The plane between two adjacent bodies of dissimilar rock.
- To touch; to come into physical contact with.
- To establish communication with something or someone