I found the obit for Capt. I.M. Bean which does list Gertrude and Sanborn as siblings
Waukesha Freeman December 1, 1910, page 4
CAPT. I. M. BEAN
The death of Capt. I. M. Bean at his home in Milwaukee of paralysis,after an illness that extended over
nearly a year, on Sunday, November 20, removed one of Wisconsin's most valuable citizens.
He had resided in this state since early boyhood. He was educated at Milwaukee and Carroll college, and on the threshold of young manhood entered the service of the country in 1861, and gained distinction as a brave
officer in the 5th Wisconsin Regiment, with which he served two years or more, retiring with the rank of captain.
Following the Civil war he entered upon his business career and was at the head of important enterprises for
many years at Milwaukee, and until failing health admonished him to relinquish active responsibilities.
At the time he suffered his paralytic stroke early
in the present year he was in New York, being about to sail for Europe, a journey which he was compelled to relinquish.
Capt. Bean aside from his private business affairs found time to give valuable services to the public in various ways, and he was among the public spirited, capable men, who aided materially in making the metropolis one of the most progressive cities of the country.
A Waukesha, where much of his early life was passed and from where entered the military service soon after he had
begun a professional career,there are many who sincerely
regret his demise.
Capt. Bean is survived by one sister, Miss Gertrude Bean, who made her home with her brother; one brother, Sanborn Bean, Waukesha; one daughter, Mrs. Edgar N. Dickson,
Milwaukee, and two sons, Sidney A. Bean, New York and Irving MaC. Bean, Milwaukee.