@petester @backpalm This technique is discussed and demo'd in this thread (and others in the past)...
Here are a few examples from that thread and others showing different possibilities ~ same principle:
cube_transition_JHSv3.hype.zip (164.9 KB)
Custom Scene transition - "cube rotation" effect
Original thread here... this demo is my follow through (a few posts down from the top) on the OP's request.
SceneTrans_JHSv1.hype.zip (22.2 KB)
This demo shows animating elements while a Scene Transition occurs.
Original thread for this demo is the one sited at the very top, specifically this post.
Slat Transition_JHSv2.hype.zip (550.6 KB)
The most complex demo in this group showing animation during a "slat" ("venetian blind") custom transition.
Original thread~post here.