Alternative to nested Memory blocks for keep track of previous N samples

Hi everyone!

I need to calculate the ONLINE windowed median of a signal in Simulink. Let's say that I want to perform the median in a window of 50 samples. 50 nested Memory block is not a good idea :)

To be more specific, right now, I have a MATLAB Function that calculates something like

x(k) = f(u(k))

I want to extend this operation by keeping track of the x and use the last N samples recursively to calculate a windowed median. Something like

x_m(k) = f(x(k), x(k-1), ... , x(k-N))

I don't have any Statistic Toolbox that contain some blocks that do what I want, so any other suggestion?