45:8 After bentching, the leader says the bracha over the cup of wine. He should drink at least a reviis (approximately 3.5 ounces) so that he can then say the concluding bracha after it. If the cups of the other diners are “pagum” (i.e., already drunk from – refer back to 45:3), he should pour a little from his cup into theirs after saying the bracha on the wine but before drinking from it. In this way, he rectifies their cups and they can also say a blessing on fit wine. If their cups are empty, he should likewise pour some wine from his cup into theirs. The other diners should not taste the wine until the leader has done so. If, however, everyone has his own cup of fit wine, each may bless and drink and they need not wait for the leader to go first. It is a very good course of action to give each diner his own full cup when possible.
45:9 If the leader does not want to drink the wine, some authorities permit another diner to say the bracha, drink the wine, and say the concluding blessing after it. Others, however, disagree and say that only the leader can bless on the cup used for bentching. It is proper to follow this second opinion.