Foreground, luma matte, background - key

Foreground, luma matte, background - key

1. Place video clip in Primary Storyline

2. Place black and white hi con matte as Connected Clip above clip in Primary Storyline

3. Select the Connected Clip and in Inspector Video Compositing Blend Mode, select either Stencil Luma or Silhouette Luma depending on whether you want black or white to cut the hole.

4. Place another video clip above the first connected clip and in Inspector Video Compositing Blend Mode, select Behind.

Maybe there's another way but this worked.