Avalon ST Multiplexer -> is it possible to concatenate?

Let's say I concatenate them in the following way:

So, how will the inputs in0 through in19 be scheduled on the OUT output?

The in0 .. in19 are packet based 16bits width inputs (with start-of-frame and end-of-frame signals).

How should I configure the MUX0 and MUX1 so that on the OUT port will be observed packets in0, in1, ... in19 in this certain order (in0, in1, ..., in19)?

Thanks!