Q. Re- question 3044 above on arranging a group of women and having one read the Megila for the others. You mentioned that is is improper to have a woman read the Megila for many women. How many is many?
A. Horav Shlomo Miller’s Shlit’a opinion is that definitely ten or a minyan would be considered many.
However, even three are also a ‘rabim’ or multitude in regard to tumah (impurity), therefore when possible should be avoided.
The Rov maintains that in need, when otherwise the women would not hear the Megila at all, as mentioned before, it is permitted.
A similar opinion is to be found in Chasukei Chemed (Megila 4a), and he maintains that three is also a ‘rabim’ as is the case on the zimum prelude to benching, which is the source of the opinion of the Korban Nessanel quoted by the Shaarei Tzion. He also asserts that when in need, one woman can read for many.
Rabbi A. Bartfeld as advised by Horav Shlomo Miller and Horav Aharon Miller Shlit’a