Yes, it is possible to schedule more than one webinar for the same time, but you can only host one webinar at a time.

If you are already in a webinar and need to leave without ending it for everyone, you can promote any staff member or attendee in the webinar to be organizer so the session can continue on without you while you switch to the next webinar.

If you attempt to run more than one webinar at a time, you will see a "A session is already running" notification. To join the other webinar, you must leave the current one.

If your organization needs to host multiple webinars at the same time, you can upgrade your plan to add additional organizer seats (these individuals would each get their own account with which they can schedule and host their own webinars).