Yes that did it!! Thank you so much! 

Hi there !

Check out my edited post above; this should do the trick for you.
Let me know if you have any questions

Thanks for your response! When I try this approach, the input is the single video but the output is the whole video 5 times in each rectangle. I'd like to have the video only once across all 5 shapes so that it looks deconstructed and only parts of it are visible. Sorry if my question is/was unclear! 

I will be able to check out the video a little later.

Thanks again!

Hi there! And welcome to the Isadora community forum.

EDIT; Addressed the issue better.

It sounds like you are Masking the input. To do so, follow the next steps;

1. Attach your Video to a Projector
2. Double Click on the Projector to open Izzy map
3. On top press 'Input' until you are in 'Input' mode
   
4. Add a Composite
5. It automatically creates Rectangle 1 for you.
6. Go to Sub-slice options and put it on Substract (basically, we say to make everything black)
   
7. Create a new Rectangle (this is going to by our doorway)
8. Set this Sub-slice to 'Invert', basically from our negative this is going to remove that part so that we can see through it.
9. Set your Window Mode to 'Split H' so that we have both our input and Output visible. Works nicer ;)
10. Repeat for Layer 2 - 5
11. Close Izzymap
12. Check your composition using the top menu (Output > Show Stage Preview)

See the attached file.

IzzyMap - Doorway

Hope this helps, if I misunderstood you please let me know as well :)

We also have a YouTube video on this topic on our YouTube channel. Ryan explains the topic in his Build it! series.