I just tested zoom to the church broadcast system and it was fairly easy to setup. I used a $15/month account. Here are quick instructions:
Login to Zoom and enable Custom Live Streaming Service:
1) Sign in to the Zoom web portal.
2) Click Account Management > Account Settings.
3) Under "In Meeting (Advanced)", click the toggle next to "Allow live streaming the meetings". This option is a long way down the list.
4) Click the "Custom Live Streaming Service" checkbox to enable it.
Setup your meeting in the Church WebCast portal at https://webcast.churchofjesuschrist.org/#/eventManager
Under "Select your encoder" Choose "Other"
I also enabled "High Bandwidth Encode"
Once the event is created, you can obtain the RTMP URL and Stream Name:
1) On the meeting select "setup" next to the gear icon.
2) Go to the "Other Setup" tab.
3) Copy the RTMP URL
4) Copy the Stream Name
Now go back to Zoom and start your meeting and enable the stream.
1) Start Meeting
2) Click on "More" at the bottom of the zoom window
3) Click on "Live on Custom Live Streaming Service"
4) Your browser will open and you may need to login to Zoom.
5) Paste the "RTMP URL" into the "Streaming URL"
6) Paste the "Stream Name" into the "Streaming Key"
7) You can also past a link to the live webcast in "Live Streaming page URL"
8) Click "Go Live!"
Zoom does remember the previous Streaming URL and Streaming Key. If these changed it will timeout and then allow you to update them.
I hope this helps.