  A new strategy, using Darboux transformations, of finding self-switching
solutions of $i\dot{\rho} = [H, f({\rho})]$ is introduced. Unlike the previous
ones, working for any f but for Hamiltonians whose spectrum contains at least
three equally spaced eigenvalues, the strategy does not impose any restriction
on the discrete part of the spectrum of H. The strategy is applied to the
Bloch-Maxwell system.
