The general solution of SUSY intertwining relations for three-dimensional
Schr\"odinger operators is built using the class of second order supercharges
with nondegenerate constant metric. This solution includes several models with
arbitrary parameters. We are interested only in quantum systems which are not
amenable to separation of variables, i.e. can not be reduced to lower
dimensional problems. All constructed Hamiltonians are partially integrable -
each of them commutes with a symmetry operator of fourth order in momenta. The
same models can be considered also for complex values of parameters leading to
a class of non-Hermitian isospectral Hamiltonians.Comment: 14 page