  Supersymmetrical (SUSY) intertwining relations are generalized to the case of
quantum Hamiltonians in Minkowski space. For intertwining operators
(supercharges) of second order in derivatives the intertwined Hamiltonians
correspond to completely integrable systems with the symmetry operators of
fourth order in momenta. In terms of components, the itertwining relations
correspond to the system of nonlinear differential equations which are solvable
with the simplest - constant - ansatzes for the "metric" matrix in second order
part of the supercharges. The corresponding potentials are built explicitly
both for diagonalizable and nondiagonalizable form of "metric" matrices, and
their properties are discussed.
