  A finite group generated by four Z_3 transformations is applied to lepton
families in a supersymmetric model, resulting in the charged-lepton masses m_i
being proportional to v_i^2, where v_i are three vacuum expectation values.
This may be relevant in obtaining the Koide formula m_e + m_mu + m_tau =
(2/3)(sqrt{m_e} + sqrt{m_mu} + sqrt(m_tau})^2.
