When the Onix gets closer to the group, the rock types all look up at the Onix as someone else who is native here, a potential ally. And the ice types all seem immediately wary. The fighting does stop... but only for a moment. Several of the Swinubs on the side of the ice-types decide to strike first, launching some powder slows at new group.

For the people who can hear the thoughts of pokemon, while most of them are absorbed in the battle at the moment, the rock types appear to be defending their home and the ice types appear to have fled out of their home, and gotten in this fight as a result. That's all that can be clearly discerned up in the midst of the fighting, though.