creating random n*n matrix satisfying particular constraints using matlab?

Hello all,

i have following code to create n*n matrix(say n=5 this time) which is following certain constraints.

 function selectingset

 % n = input ('Enter Num_Nodes  :');
 % inputData=input ('Enter inputdata  :');

n=5;
inputData=[5 1 2];

 for z = 1:n

    f   = inputData(1,1); % f= Demand
    S   = inputData(1,2); % S= Source node
    T   = inputData(1,3); % T= Termination node

 [idx,p] = sort(rand(n-1,f));
 M = accumarray([reshape(p+(p>=T),[],1),repmat([1:S-1,S+1:n]',f,1)],1,[n,n]);
 M(1:n+1:n^2) = 0;

 end
 disp(M);
end

So, my o/p from following code is---

     0     0     2     3     0
     0     0     0     0     0
     0     0     0     0     3
     0     4     1     0     0
     0     1     0     2     0

Note that as in given code

input S=1, so column 1 is zero and

As T=2, so row 2 is zero.

As f= 5, so sum of row S(i.e. S=1)=Sum of column T(i.e. T=2)= 5

and i am making diagonal elements zero.

all the remaining rows and columns, sum of row(i)=sum of column(i)

Now, How can i modify code such that row(1,3) will always come zero in output but output still follows previous mentioned constraints.