Seamless animation between two Windows

Is it possible to seamlessly animate between two Windows.

I have the following code in Home.xml

<animation effect="slide" start="0,0" end="0,-1080" time="400">WindowClose</animation>

and the following in MyVideoNav.xml

<animation effect="slide" start="0,1080" end="0,0" time="400">WindowOpen</animation>

What I would like to happen is when switching between Home and MyVideoNav the Home window scroll upwards off the screen and the MyVideoNav window scrolls in from below at the same time so it's seamless. However using the two animations above they play one after the other, meaning the Home window scrolls up off the screen but the MyVideoNav doesn't start scrolling in until after the Home animation has finished.

If there any way to get both animations to occur at the same time?