Getting playback to parse correctly. Ver 1.3 and 2.0

Good day all. Working with a version of The Ash Grove, where we have a first measure that has one beat ( a lead in measure ), followed by an "A" part that gets repeated once, then a "B" part that gets played once, and then a final ending, which is to be played after the "A" is done with it's second go around. The first repeat is easy, as is getting the "B" part to play next. The problem comes when trying to go to the 'beginning' by way of the D.S. and then ignore the first and second endings but jump to the third ending. The D.S. works fine, but we've tried just about every combination to perform that final jump with no luck. I recognize that there might be a problem with MuseScore and it's interpretation and abilities to perform this trick, so I'd appreciate both the Correct method to score this as well as what MS might want.
In your debt ... again. Al