What will happen if we innoculate five strains of Bacillus subtilis, B. cereus, B. amyloliquefaciens, B. pumilus and B. sphareicus together in a broth medium? Whether they all flourish well or start outnumbering each other in death phase.
It will certainly depend on the medium and on the species of Bacillus inoculated and even on the strain of the same species. Different species and even different strains of the same species display different growth rates in the same medium.
You may check examples in this paper by Warth (1978),