It would be useful to be able to add a note at the end of the exhibition record.

That way, researchers could provide critical information to the reader without having to insert it in the title.

For example:

Berlin, Kunstsalon Paul Cassirer, Dritte Ausstellung [Sammlung Gottlieb Friedrich Reber, Barmen], January 1–20, 1913, no. 36 (as “Aita Parai”)

I would suggest placing the bracketed information at the end in a short sentence, like: "Exhibition of the artworks belonging to the Sammlung Gottlieb Friedrich Reber, Barmen."

Or

See the example from the published Johns Catalogue Raisonné, attached.