  The energy spectrum of the three-particle Hamiltonian obtained by replacing
the two-body trigonometric potential of the Sutherland problem by a three-body
one of a similar form is derived. When expressed in appropriate variables, the
corresponding wave functions are shown to be expressible in terms of Jack
polynomials. The exact solvability of the problem with three-body interaction
is explained by a hidden sl(3,\R) symmetry.
