There are multiple scenarios to consider related to simultaneous events. We'll start with meetings:
Q: Can I host multiple Zoom meetings simultaneously?
Q: Can I attend multiple Zoom meetings simultaneously?
The following scenario is related to webinars:
Q: If I am the host of a webinar, and the co-host has started that webinar, can I start a separate meeting or webinar?
A: No. Zoom will give you the option of ending the webinar first in order to start your new event.
If you need to host simultaneous sessions, you may want to consider using Google Meet instead, or perhaps a combination of both Meet and Zoom. We recommend that you just setup a test to simulate your needs, then you'll know for sure how it will work.