i dont know if they're a feature of Jewish weddings but they're certainly in Christian ones.

they're usually close friends/family who help with the administrivia both in the run up and on the day. they're also the women who - on the day - help the bride with her dress (if needed), hold her stuff (brides dont generally wear purses :) ), fetch-and-carry etc.

they're the people who do the things you're too busy/panicking to :)