  We consider the effect of isotropic impurity scattering on the exotic
superconducting states that arise from the usual BCS mechanism in substances of
cubic and hexagonal symmetry where the Fermi surface contains inequivalent but
degenerate pockets (e.g. around several points of high symmetry). As examples
we look at CeCo$_2$, CeRu$_2$, and LaB$_6$; all of which have such Fermi
surface topologies and the former exhibits unconventional superconducting
behavior. We find that while these non s-wave states are suppressed by
non-magnetic impurities, the suppression is much weaker than would be expected
for unconventional superconductors with isotropic non-magnetic impurity
scattering.
