  We consider $\mathcal{PT}$-symmetric ring-like arrays of optical waveguides
with purely nonlinear gain and loss. Regardless of the value of the gain-loss
coefficient, these systems are protected from spontaneous
$\mathcal{PT}$-symmetry breaking. If the nonhermitian part of the array matrix
has cross-compensating structure, the total power in such a system remains
bounded -- or even constant -- at all times. We identify two-, three-, and
four-waveguide arrays with cross-compensatory nonlinear gain and loss that
constitute completely integrable Hamiltonian systems.
