Creating a "Live With" Experience similar to Instagram

Hi all – I looking to build a feature similar to "Live With" that Instagram has.

To describe the feature at a basic level: I want a livestream of two streams that originate from two separate mobile apps. How this would work is:

• Participant A starts livestreaming from their iOS/Android
• Participant B is asked to join the livestream.
• Participant B starts livestreaming from their iOS/Android
• Viewers see a single stream of Participant A and B speaking

I'm a noob to the AWS video products but I couldn't figure out (1) whether this is possible, (2) what tools could be composed to replicate this experience