Hi @tonymarchi52,
Yes, this is possible. You can have several QuickBooks Online (QBO) company on a single QBO account.
Please keep in mind, each company you add will be a separate paid subscription. You can access them all with the same login info. This allows you to switch in-between them whenever you need it.
See more details in this article: Create or add another company. You'll find the steps on how you can add, as well as a new company in QBO.
In case you have QBO companies under different QBO accounts, take a look at this article: Sign in to multiple QuickBooks Online companies with one user ID. It will allow you to add all those companies using different user IDs (QBO account) under a single user ID of your choice.
Have other questions in mind? Place them below, and I'll get back to you as soon as I can.