If I arrive late to a shabbos meal, and the others at the meal have already made Hamotzi on Lechem Mishneh, when I join them and wash for bread, do I need Lechem Mishneh of my own as well? Or can I rely on their Lechem Mishneh, and make Hamotzi on a slice of challah alone?
It seems to me that this should be okay, because, at a regular meal, when the Ba'al Habayis makes Hamotzi on Lechem Mishneh, the others there eat just the slice handed to them - in other words it seems they rely on his Lechem Mishneh. The difference is, that I join the meal later. So, can I rely on his Lechem Mishneh too?
This question is not whether I should (obviously I should make Hamotzi on Lechem Mishneh when I have the chance), but whether I must (for instance if I'm trying to save more challahs for the next meal of shabbos.)