@MelissaPicchion ...
Unfortunately, I do not know of a way to do this within Canvas Studio. Each user in Canvas would have their own Studio "library" to store their own videos. And, while there are capabilities to share videos with one another, I've not heard or seen anything in any Canvas documentation that would allow two or more users to combine the videos together...at least not doing so in an online capacity. You might try downloading the videos from Studio, using a video editor offline, and then re-uploading the videos to one of your Studio accounts to see if that would meet your needs.
Good luck!
