I found a way to do this using the Conductor Mode and shortcuts. It's working really well.

- Enter Conductor Mode. (click the conductor icon on the icon menu)
- Enable Control by QWERTY Keys in the conductor setup window.
- Enable Loop Section (NUMPAD 1).
- In the Loop Section settings, set the loop length to 4 bars.
- Press the X key (conductor shortcut; this will set the loop length to 4 bars starting on the current bar).
- Start playback.
- The first 4 bars of the song will start looping.
- When you are done practicing the first 4 bars, hit NUMPAD 1 to disable Loop Section.
- When playback reaches the next section you want to practice (bar 5 for me), press the X key. This will re-enable Loop Section with 4 bars, this time starting at bar 5.
- Repeat until the song is learned!

After this, I go back and set the Loop Section to a larger size, like 8 bars or more... and I keep increasing that loop length until I've memorized the song.