How do I setup multiple companies in quickbooks using one email
Each account requires a separate subscription. You can get more subscriptions by going to QuickBooks.com and clicking by now and instead of creating a new account, click the link that says sign in.
If your company is all 1 EIN and you just want to manage properties separately, you might want to look into setting up the properties as locations, projects or each location as a separate customer. That way its all under 1 subscription but you can run reports based on individual properties if you want.