I ran following scenarios:
1) p1:foreground, contains p2, p2 contains p3:exclusive, no other process could not be run with p1, suggesting it is of exclusive nature.
2)all processes are exclusive, could not run multiple processes suggesting sub processes are not affected by the precedence.
2)p1: background, contains p2: foreground, p3:exclusive, no other process could be run with p1, again suggesting it is of exclusive nature.
3)p1: background, contains p2 and p3, both are background, no other process could run.
4)p1:foreground, contains p2 and p3 both background, only background processes could be run along with p1.
I think master process automatically takes the highest precedence of the sub processes.