One line, one metric

Hi,
I haven't a good idea to name this topic, maybe there is a scientific and precise term but I don't know it
Here is the point:
Actually musescore allow polymodality (one line, one key)
But some scores have different metric for each line (ex: George Benjamin - Piano figures: Alone)
In fact, there is still a method to do it in Musescore BUT, "graphically", we can't show 2 different metric for each line

I linked:
- Polymodality example
- Firsts measures of "Alone" (Perusal score: http://scorelibrary.fabermusic.com/Piano-Figures-22275.aspx)
- The 2 firsts measures of "Alone", written in actual Musescore

Thanks