Yes. You can accomplish this by adding the Thrifty lines to your rate plan as follows:

To add Thrifty lines to an existing location: 

• Click on Order Business Services from the AT&T BusinessDirect^® home page.
• Select Change Service on the left-hand navigation bar.
• Select the Master Customer Number (MCN) and existing location where you want to place the Thrifty lines.
• Select Add Telephone Numbers to Existing AT&T Location.

 To add Thrifty lines to a new location:

• Select Outbound under the New Service Switched Voice section on the left-hand navigation bar.
• Select Add New Location.

 With both order types, if you select Thrifty Account Number as the type of phone number, it will move all of the lines from your Thrifty account to your AT&T rate plan. Alternatively, you can select Thrifty Telephone Number(s) and enter just the individual Thrifty telephone numbers you wish to move. Upon order completion, Thrifty billing will stop and the selected Thrifty lines will be moved to your AT&T rate plan.

 Please note that calls made prior to moving your Thrifty lines to your AT&T rate plan will be billed to the Thrifty account. If you wish to request a billing adjustment, please submit a billing inquiry form and attach the proper documentation.