AWS Ground Truth - Lableling WHEN something occurs in video

Question

I'm creating multi-classification video templates in AWS Ground Truth: https://docs.aws.amazon.com/sagemaker/latest/dg/sms-video-classification.html

I need to submit a 1-2 minute video to Ground Truth, have person select:

1. What is in the video (multi-select from list)
2. When the label in the video starts/stops For example, I submit a video with a cat sitting and then walking. I need the person to select "walking" and "sitting", but also when in the video the cat starts/stops walking.

I can program item 1 easily from the documentation, but item 2 is more difficult.

Here is the list of crowd elements supported by Ground Truth. I've tested each one but do not see a work-around. The slider is possibly one way (tying the start/stop video times to the slider values). https://docs.aws.amazon.com/sagemaker/latest/dg/sms-ui-template-reference.html

Has anyone had luck creating more complex video templates with Ground Truth?