Assuming your vector is divisible by 5, you could do this:
v = your vector
g = reshape(v,5,[]); % reshape v into a 5 x N matrix
Then your groups of 5 would be g(:,1), g(:,2), g(:,3), ... etc.
You DO NOT want to have variables named group1, group2, etc. because that is very hard to manage downstream in your code, forcing you to use eval( ) to process them in a loop, etc. For a full discussion of why this is discouraged:
