If you want to broadcast your own camera along with another person's camera on a live stream, it is possible! However, to get it working well, it will take some dedication to understanding some of the finer points of video and audio inputs from your end.
First, you can easily broadcast a Zoom meeting to Uscreen as a Live Event via RTMP. There's drawbacks though. You've probably noticed that Zoom quality isn't the greatest for its audio and video. This is because Zoom is reducing the quality to save bandwidth costs and they don't let you set the quality yourself.
Zoom is probably fine if you're just having a chat with another person and want to stream that as a live event. However, if you want to get music involved or play media for your users to watch, it's not going to work. Zoom doesn't allow you to play a media file directly and if you wanted to, you'd have to basically share your screen and play the media. The quality will not be good enough to show your viewers.
So, how do we make this work? One fantastic software is Wirecast Redezvous. It's basically like creating your own private Zoom with the ability to change what you're broadcasting. It can be you chatting with someone else in another city and then you can easily switch to playing a film or broadcasting different camera angles or music.
It's not cheap though. Wirecast is $599 for it's cheapest option and that allows you to display up to 2 remote webcams. So you're limited to chatting with 2 friends. However, if you're willing to make the time investment you can take your streaming to the next level!