Playback of sustained notes in loops

I think there used to ba a feature that would allow the program (Sonar X-1 is what I have now) to look back to the beginning of the work and play any thing that is currently active. For example, I am working on a certain part of the composition and have it looped over a few measures. A couple of the other instruments are long notes that begin outside the loop, so that those instruments do not play when the loop starts and repeats (unless I go and start playback before those notes begin). I may have just dreamed it, but I thought ther was a setting that would allow the program to look back and pick these instruments up, but I can't find the setting in X1.