How to turn off alerts for Calendar events on multiple iOS devices

I have a bunch of alerts I created for repeating events in my calendar. I recently decided I didn't want an audible alert for most of these, so I went through and removed the alerts on my iPhone. However they keep coming back. I guess this is because the Calendar events are shared with my iPad and my two Macs and when I sync the alerts are reinstated. How do I find the "master" account and remove these alerts so they will no longer be on any of my iOS or MacOS devices?