Kiddush, havdalah, a bris, kiddushin, or any mitzvah for which wine is required should be made on wine that is not pogum, that somebody has not already drunk from. This applies not only to the person who is making kiddush, but even to the people who wish to be yoitzei kiddush and drink some of the wine. Although they do not have to drink in order to be yoitzei kiddush, it is still preferable - mitzva min hamuvchar - if they do drink. Ideally, they should drink from wine from which no one has drunk yet. One of the solutions to achieve that goal is for the person making kiddush to pour some of the wine from his cup into each person’s individual cup before drinking from it. Alternatively, they can each have their own cups prepared with wine in advance. Another option is that they they actually drink directly from the same cup on which the person made Kiddush, as when the wine has been drunk from but is still in the original cup, it is not considered pogum, defected.