No. Online is only good for 1 return per account. But you can use the same email address for 5 accounts. How to start another return in the Online version
Or go to the IRS Free File programs
Free File: Do your Federal Taxes for Free | Internal Revenue Service
The Desktop CD/Download program can do unlimited returns.
With online TurboTax you get
one return per fee.
You can use the same email address but each user needs their own account and user ID. If you use the same one for a second return, the second one overwrites the first one and it is lost forever.
When you use Desktop TurboTax, which you install from a CD or download to your own hard drive, you can prepare and e-file multiple returns for the cost of the software. You can e-file up to 5 Federal returns—more if you mail the additional ones. If you have multiple returns to prepare for family members, Desktop is more cost effective.