75:9 One must light candles in all rooms that are being used. If a man is at home with his wife, because she blesses over the candles in one room, he does not need to bless over candles he lights in other rooms. If he is spending Shabbos elsewhere and has his own room (even just for sleeping – Mishnah Brurah 263:29), he should light candles and recite the bracha. If several people are sharing a room, they should all contribute towards the cost of the candles; one of them lights and recites the bracha with the intention to include the others. They should likewise have the intention to be included in his bracha. If the guest is sharing a room with his Jewish host, he does not need to light because his wife is lighting for him at his home. Unmarried students who are away from home, if they have their own room, must light and recite the bracha. They should all contribute toward the cost of the candles and one recites the bracha for all of them. The candles need to continue burning until they return to their room. If they do not have their own room, since they do not have wives lighting for them elsewhere, they must each give a coin to their host in order to acquire a share in the candles. (Mishnah Brurah 263:34 says that the host may give them a share as a gift.) One who regularly eats at his host’s table is considered like a member of the household and need not contribute towards the candles. 75:10 If there are several women in the same house, the custom is that each lights her own candles and recites her own bracha. This is because the increase in light means an increase in the Shabbos joy. They must be careful that two women do not light their candles in the same candelabra but in a difficult situation one may be lenient in this matter.