Wedding attendant (5)
(Other definitions for usher that I've seen before include "Show to seat" , "Escort (to a seat)" , "Cinema or wedding attendant" , "may be match participant" , "Cinema or wedding official" .)
(Other definitions for best man that I've seen before include "Groom's primary attendant at wedding" , "Bloke participating in match" , "Bridegroom's mate" , "May he win!" , "Principal groomsman at a wedding" .)
(Other definitions for bridesmaid that I've seen before include "Attendant at wedding" , "match participant" , "one's holding up train perhaps" .)