Trying to find a short story/novella about several people connected by telepathy. The two hands were a pair of twins who moved in response to the “brain,” also a separate individual. I read it in the early 1950’s.
"Baby Is Three", a 1952 novella by Theodore Sturgeon; first published in Galaxy Science Fiction, October 1952, available at the Internet Archive; expanded into the 1953 novel More Than Human. You may have read the novella in the original magazine, or in the 1953 anthology Children of Wonder edited by William Tenn.
The story describes the creation and "bleshing" of a new life form, Homo Gestalt, on Earth. It is formed by the symbiosis of four or more humans with paranormal abilities. One person, the "head" of the organism, assembles and directs the various parts through telepathy, another is the "hands" of the organism, able to move and change physical objects by telekinesis, the third and fourth persons are twins able to teleport at will, and the fifth person of the organism is a silent baby with Down syndrome with a brain like a computer and who acts as the "brain". "Bleshing" is how the organism describes its own completeness and functionality. The plot follows the psychiatric evaluation of a fifteen-year-old boy named Gerry, who believes he has murdered his caregiver Miss Kew for endangering the "bleshing" of his new organism.