There is a Halachic question mark as to the exactly obligation for women to hear Havdalah. Some authorities are of the opinion that Havdalah is a time bound positive mitzvah from which women are exempt, some are of the opinion that it is not time-bound and women should make Havdalah. The same disagreement applies to the Havdalah candle. If it is a time bound positive mitzvah then women should not light the candle and make a blessing over it. If it is not they can. See, Bi'ur Halacha – Mishna Berura siman 296.
Therefore women should make Havdala only if there are no men present. If there is a "man" over the age of Bar MItzvah he should make Havdala. If there are only women there is no problem with one of the women making Havdala for the others although there is a certain amount of uncertainty as to whether the lady reciting Havdalah makes the Bracha over the candle or not, see Shemirat Shabbat Kehilchata 61:24.
