how to set up two different populations in a segregation model code?

I have a general code for the segregation model like the following:

%% n = grid_size;

grid_size = 50;

n = grid_size;

n2 = n^2;

grids = zeros(n);

emp = round((percent_empty/100)*n2);

two = round((percent_two/100)*n2);

tot = emp + two;

rand_loc = randperm(n2);

init_emp = rand_loc(1:emp);

init_two = rand_loc(emp+1:tot);

init_one = rand_loc(tot+1:end);

grids(init_emp) = 3;

grids(init_two) = 2;

grids(init_one) = 1;

figure, imagesc(grids), colorbar, axis([1 n 1 n]);

% frame = getframe;

% writeVideo(writerObj,frame);

how could I insert two populations in this code, that is population 1 are unsatis ed with their location if the number of their neighbours that are from population 2 is u1 or higher, and population 2 occupants are unsatis ed with their location if the number of their neighbours that are from population 1 is u2 or higher. Beside this, p1+p2 is less than 100; the rest can be empty.