[Plugin:Event Registration] Multiple Calendars

We currently have an events calendar on our site that allows us to add anything like deadlines, open social events, etc that are either not actually events or do not require any type of registration. I would like to have only have one events calendar on my site. So, how can I either create events on your calendar that do not require any registration or is there a way to integrate your functionality with my existing calendar and only create event registrations for the events that need it? Thanks!

https://wordpress.org/plugins/event-registration/