  We study a spatial cyclic predator-prey model with an even number of species
(for n=4, 6, and 8) that allows the formation of two defective alliances
consisting of the even and odd label species. The species are distributed on
the sites of a square lattice. The evolution of spatial distribution is
governed by iteration of two elementary processes on neighboring sites chosen
randomly: if the sites are occupied by a predator-prey pair then the predator
invades the prey's site; otherwise the species exchange their site with a
probability $X$. For low $X$ values a self-organizing pattern is maintained by
cyclic invasions. If $X$ exceeds a threshold value then two types of domains
grow up that formed by the odd and even label species, respectively. Monte
Carlo simulations indicate the blocking of this segregation process within a
range of X for n=8.
