"our side business" ??? Is this a mulit-member LLC/Partnership or an S-Corp?
If this is for 2019 : https://turbotax.intuit.com/personal-taxes/past-years-products/
If so then you need 2 separate programs ... One of the personal ( Deluxe will work) and the Business versions.
With the online version, no. The online version of TurboTax 2019 is shut down permanently and forever so they can prepare for the 2020 tax filing season.
With the CD version that you purchase and install on your computer, you can do as many individual returns as you want. But you'll have to print, sign and mail them all for 2019 taxes. E-filing is closed for the 2019 tax filing season.
If the business is a multi-member LLC or partnership (would have to be at least one of those if two or more owners and those owners are not married to each other and filing joint) then you will have to purchase a separate program for the business taxes, called TurboTax Business.
For the 2020 tax filing season which will start in January of 2021:
With the online version of Turbotax, one account, one return. Period. End of Story. You have to pay for each tax return completed and filed with the online version.
For a business tax return, be it a 1065, 1120 or 1120-S, you can not use any flavor of the online version of Turbotax. You have to purchase and install the CD version of Turbotax Business, which is only available for Windows computers.
Same answer ... you will need 2 programs and the Business version is only available as a Download for Win OS.
They are available as a pre order now at a discount ... start with the Deluxe and only upgrade if you feel the need for more assistance :