Hmm it's not directly possible from WDL, but you could add every frame from every motion and add the first die frame after it,
f.ex:

move1,die1,move2,die1,move3,die1...
now you just have to calculate which frame is the nearest (move2 for example), then you set the current frame to move2 and blend it to die1 after that you just play the die animation, maybe there is a better solution with the SDK