Two vehicles filled with a company of people (7)
I believe the answer is:
caravan
'company of people' is the definition.
The definition and answer can be both groups as well as being singular nouns.
Perhaps you can see an association between them that I don't see?
'two vehicles filled with a' is the wordplay.
'two vehicles' means two substitutions for 'vehicle'.
'vehicle' becomes 'car' (car is a kind of vehicle).
'vehicle' becomes 'van' (van is a kind of vehicle).
'filled with' is an insertion indicator.
'car'+'van'='carvan'
'carvan' placed around 'a' is 'CARAVAN'.
Can you help me to learn more?
(Other definitions for caravan that I've seen before include "Group of desert voyagers" , "Group travelling together across a desert in single file" , "Desert convoy" , "Towed home" , "Holiday vehicle" .)