When using Turbotax Online software you must open a new account for each return that you file. However, you can file up to five returns using the same e-mail address. It may be more cost-effective to use Turbotax CD software unless the other returns qualify for TurboTax Free edition. Please view the TurboTax FAQ below for more information.
https://ttlc.intuit.com/replies/3288574
