Taunt and pHazers will take care of these easily. Admittely though, Hippowdon and Skarmory may not enjoy taking a Crocune Surf.
Perhaps an easier method, and one that many teams can do, is to take advantage of Crocune's and Crotomb's slow set up, and send in a pokemon will faster set up e.g. Salamence, Gyarados, SD Scizor. Alternatively, I could just send in a hard hitter that will deal damage more quickly than Crocune/Crotomb can heal off e.g. CB Tyranitar (who won't take enough damage from Suicune), Salamence.
As well, you can also bring their HPs down to low, and send in a pokemon that can finish them off as they spam their CMs, even if that pokemon wouldn't be able to swap into a boosted Surf/Dark Pulse e.g. Lucario (though he can take Spiritomb's Dark Pulse).
Imagine the same strategy, except you miss when you try to finish them off due to Double Team. Sounds fun?