There was indeed a big fight between them. I do not remember the year exactly. And it was before pre internet eras.
I mean there might be social tensions here and there, but I am not aware any large scale conflict between the two groups. You are describing a pretty violent situation.
Really, I would be interested in finding out more about this matter. Even though Pakhtuns form majorities in N. Baluchistan there is hardly an active movement to split the provinvce. Generally Pakhtuns and Baluchis have seen each other as brotherly groups, similar in many respects.