  The standard three-state voter model is enlarged by including the outside
pressure favouring one of the three choices and by adding some biased internal
random noise. The Monte Carlo simulations are motivated by states with the
population divided into three groups of various affinities to each other. We
show the crucial influence of the boundaries for moderate lattice sizes like
500 x 500. By removing the fixed boundary at one side, we demonstrate that this
can lead to the victory of one single choice. Noise in contrast stabilizes the
choices of all three populations. In addition, we compute the persistence
probability, i.e., the number of sites who have never changed their opinion
during the simulation, and we consider the case of "rigid-minded" decision
makers.
