The two ways to get tempo synced transitions between sections of music is with Transition Regions and Magnet Regions. Essentially a transition region allows you to assign conditions to exit the region, and a magnet region allows you to assign conditions to enter the region- both of these have Quantization settings to allow these exits/entrances to occur in sync with the event’s tempo. Transition regions have the handy feature of displaying the quantization interval as green lines over the tracks, here you can see an event with two transition regions. The “To Marker B” section is quantized to a half note, and “To Marker B” is quantized to 1 bar:
By changing the “Section” parameter at the top, I can select which section of music will play, and the transition to each section will only occur on a half note or one bar respectively.