Destiny FOV cameras- how to view multiple cameras simulataneously

A Destiny animator gave a speech at GDC and described their method of getting around distorting the FPS animations when shifting FOV by making two cameras, one for the arms that was locked at 74 FOV and the other camera which the player could adjust. This is the video:

Timestamp: 40:35

How could one go about viewing multiple cameras simultaneously? I don’t know how you could pull this off in BPs.

How about this?

https://forums.unrealengine.com/development-discussion/rendering/1433839-how-to-implement-panini-projection-for-first-person-weapon-separate-fov-for-weapon

@ClockworkOcean Thank you for finding this!!