I came across this photo in the Wikimedia Commons: Ontario Society of Artists Hanging Committee, 1927 (I0010428).tif.

With the help of Barbara Mitchell (curator at the Arts and Letters Club of Toronto) and a reference librarian at the Art Gallery of Ontario library, the people were identified, and I updated the metadata: from left to right they are Emanuel Hahn, Fred S. Haines, J.E.H. MacDonald, Dorothy Stevens, Herbert S. Palmer, Manly MacDonald and Frederick Loveroff. All the men were members of the Arts and Letters.
At the time Dorothy Stevens couldn’t join because she was a woman, but I think she was a member of the Heliconian Club. Her entry in the Canadian Women Artists History Initiative has scans of many reviews. The Star review of that OSA show doesn’t mention her name but the list of works she helped hang gives a sense of what a great show it must have been. As for her examples of her work, there’s a 1918 drawing in War Art in Canada: A Critical History by Laura Brandon, one of the wonderful books from the Art Institute of Canada. Her work is in the Art Gallery of Ontario and the National Gallery of Canada.

What a face! That portrait was taken by M.O. Hammond, another member of the Arts and Letters.
Category:Ontario Society of Artists has a lot more great photos, including hanging committees from other years, but any further identifications will have to wait.