You can create Projects that employees can clock into on their web bundys.

When you export payroll, you can then filter employees according to the projects they were on during the payroll period.  Doing so creates a grouping in time.

To add projects, go to Company Setup> Organization > Projects.

Click Add Projects. The Add Projects form will pop up. Enter the Project Name and Project Description, then click Add.

Note: Employees can clock into multiple different projects during a payroll period.