Fitting in with everyone in Victoria? (12)
I believe the answer is:
installation
'fitting' is the definition.
(thesaurus)
'with everyone in victoria?' is the wordplay.
'with' is an insertion indicator.
'everyone' becomes 'all' (all people).
'victoria?' becomes 'station' (Victoria is a London train station).
'in'+'station'='instation'
'all' inserted into 'instation' is 'INSTALLATION'.
'in' acts as a link.
(Other definitions for installation that I've seen before include "Art exhibit in gallery" , "establishment" , "Large gallery artwork" , "The making of equipment ready for use" , "Apparatus positioned" .)