Prevent Autofilling With Rests

Forgive me if this is a feature and I've just been unable to find it anywhere (have searched endlessly through the options and did a bit of Googling but couldn't find a solution). However, I am currently assisting in re-arranging American civil war era scores for a living history group, and a lot of these songs (which they want to play traditionally but need transposed) have a habit of beginning the song with a pickup bar and then looping back to the pickup bar.

Seeing the attached image should show why the issue of auto-filling with rests arises (forgive the image quality, working with primary sources here). The pickup bar is two sixteenth note and the intention of the original arranger was for the two alternate endings to arrive back to the pickup bar and start from there.

This is fairly common in my experience in a lot of American Civil War era/old time American music (and possibly other styles but I wouldn't be able to speak with any sort of authority on those). I do have a mild solution of doing a lot of messing around with the PDF, but if I need to adjust the score at all I then have to redo the PDF.

Hopefully this is something that can be considered (or is already some hidden feature).