Ability to change meter in a song without stopping

I wish I could set different metronome settings for different sections of one song, so I could turn my metronome on and sing through a piece without having to stop, change settings, and trying to resume. If my first five measures are 4/4 but the meter changes, or if a piece has a different time signature per measure, as a lot of 20th century classical music does, it would be more useful to me as a classical musician to be able to go measure by measure and make my settings, on one track, and play the song all the way through with no stopping.

Merged into "App: tempo & time signature changes" #7