Add Executive Zooms to Google Calendar in Drop Down?

I'm an Executive Assistant I schedule meetings for myself, and 3 executives. 

At other organizations IT has set it up so my Google calendar Add-On just has a drop down where it will fill in the executive's appropriate zoom info. I can't seem to figure out how to set this up myself at my new organization. 

Does anyone know how to do this? 

Right now I'm having to log in to their zoom accounts individually, create a meeting, then copy & paste it into the calendar invite. It's quite time consuming. 

Thanks!