Q. When making a Hanuka party in a large room that was in the past used for a Shul and now is only used for shiurim and only occasionally for a minyan, can you light there the menorah at the party with a bracha?

A. Minchas Elozor (O.H. 2: 68) enumerates four reasons why we light a menorah in a shul: a) For the sake of visitors who don’t have their own. (Bais Yosef O.H. 671, Sefer Hatanya), b) To include the ones who do not know how to light or make a brocho or are negligent in doing so (Kolbo 67.), c) Persumei nisso or publicizing the miracle and remembrance of the Bais Hamikdosh (Kolbo and Bais Yosef, ibid.) d) Since historically many times we could not light outside or by un-shuttered windows, we publicize the miracle in the shul (Rivosh, Shulchan Aruch O.H. 671: 7).

In the venue you describe some of the above reasons may be absent, therefore Horav Shlomo Miller Shlit”a ruled to light without a brocho. However, he suggested that a child, old enough to understand the meaning of the mitzvah (higia l’chinuch and as part of his chinuch) maybe might recite the brochos. (see also Yalkut Yosef O.H. 13: p. 203)

Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit”a