Trendy types, including staff with parts (2-5)
I believe the answer is:
'trendy types' is the definition.
I know nothing about this answer so I cannot judge whether this works.
'including staff with parts' is the wordplay.
'including' becomes 'inc'.
'staff' becomes 'rod' (both can mean a stick or cane).
'with' becomes 'w' (abbreviation).
'parts' means one lot of letters goes inside another (one word creates a gap in ie parts another word).
'rod' enclosing 'w' is 'rowd'.
Can you help me to learn more?
(Other definitions for in-crowd that I've seen before include "Small group of popular people" , "Fashionable set" , "Fashionable group" , "jet set" , "Fashionable coterie" .)