Rolling regression per 4 Independent Variables

Hi guys, I have a regression problem.

My x = 249*48 and my y = 249*12

I am attempting to regress y(:,1) on x(1:4)n then y(:,2) on x(5:8) and so on up to the 45-48 column. I can only do this if it is y(:,1) on x(:,1), y(:,1) on x(:,2)......

could anybody help pleaseeeeee

x1=data(:,1); y=data1(:,1); %% x=[ones(size(x1)) x1]; a=x\y