animation start on slide transition

How can I start an animation (with e.g. <animate> or <animateTransform> tag) automatically after
transition to the slide where the animation should appear?

In concreto: I make a slide transition from slide number 2 (layer id="NL") to slide number 3 (layer id="EU") such that upon transition
from slide 2 to slide 3 the view zooms out from Netherlands to Europe.

I can do this manually by the SVG code below, but would like to sync the begin to the slide transition instead of pressing the key "1" with the accessKey(1) function. I think this requires modification/adding some script code, at least to detect the slide transition event.

            <animateTransform
               fill="freeze"
               dur="1s"
               begin="accessKey(1)"
               to="3"
               from="16.0"
               type="scale"
               attributeName="transform"
               attributeType="XML"
               id="zoom1" />
            <animateMotion
               fill="freeze"
               dur="1s"
               begin="zoom1.begin"
               path="M -62700 -10000 L -8970 -1350"
               attributeType="XML"
               id="move1" />