No. You can only file one return per account with Turbotax Online, so you will need to create a second account.

Tip: If you're preparing multiple returns for family members, it's more economical to switch to the TurboTax CD/Download software, which lets you e-file up to 5 federal returns at no additional cost. Here is the link to the Desktop products: https://turbotax.intuit.com/personal-taxes/cd-download/