  In this work we consider three species competing with each other in the same
habitat. One of the species lives in the entire habitat, competing with the
other two species, while the other two inhabit two disjoint regions of the
habitat. These two populations just interact on a region/interface which acts
as a geographical barrier. This barrier condition causes a drastic change in
species behaviour compared to the classical Lotka-Volterra competitive model,
showing very rich and new different situations depending on the several
parameters involved in the system.
