How can I use simulink to merge four elements in a matrix to become just one symbol?

I have tried using the embedded matlab function, but ended up gettin the error "Subscripting into an mxArray is not supported"

For example, assuming I'm receiving a 12x1 matrix element from a simulink block [1;2;3;4;5;6;7;8], I want simulink to group the first 4 elements and merge or symbolise it as 1234(i.e a single integer), and carry on like that for the next 4 elements. I.e, 5678 for the next set.

Here is what I vae put inside the embedded function: %---------------------------------------------------------- function y = fcn(u) formatSpec = '%d%d%d%d' A=0;A=length(u); y = (zeros(length(u),4,'double'));%y=yy; coder.extrinsic('sprintf','str2double'); u=str2double(u);

for n=1:4:A y=sprintf(formatSpec,u(n), u(n+1), u(n+2), u(n+3)); %y=[y yy]; end %------------------------------------------------------------

Anyone with the idea should please bail me out. Regards, Ken