The most common and most likely answer to this crossword clue is the 13 letter word GRAVE-DIGGERS
I've seen this crossword clue in The Times
G
R
A
V
E
-
D
I
G
G
E
R
S
Buddy explains!
The straight part
We know that "who may work alongside the church" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case who may work alongside the church = grave-diggers.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.