[Zubersoft]

There are actually a couple of features already in the app that may be useful for you. The first is under Settings->Library Settings and is called "Always Load Last Viewed Page". If you enable this before loading a setlist, it will save your place so that the next time you load it, you will resume your place. It sounds like this may work for what you want. If you don't want to enable this setting, you can still long press a song or setlist on the library screen, tap the overflow menu and then choose the "Load Last Viewed Page" option. Let me know if this isn't exactly what you need though.