Multiple database connection for identifying tenants

Currently we are looking different available options to identify tenants when we move to auth0
We are multi tenant system where we have tenants/organizations in the same db. We also maintain a few db instance for couple of tenants / organizations
When we move to auth0 we wanted to maintain a single db for all users. How we can differentiate between different tenants/organizations. Is it something that can be done with multiple connections?
Please let us know if there’s better way to achieve that