PowerSource article 6185 walks the user through setting up Teams in PowerSchool. Of particular interest is the comment from Laura Cowart about mass assigning students to teams (below). Team lists with ID numbers are found with the “Teams” link on the left of the PowerScheduler page.
Select all the students for Team "A" by hand from a larger group, say 8th grade, then navigate to the main PowerSchduler page. Select Functions and choose Update Selections. This is a mass change utility so you'll want to take some care here. Set your table to Students and verify that you have the correct number of students (the number you just selected by hand) in your current selection of records. If you're not sure, click on the blue link List Students to see the students included in your current selection. Click on Scheduling Functions from the breadcrumb trail, then Update Selections again from the Functions menu to return to where you can update the records. When you're ready to make the change, click on the blue link Modify Records and choose Sched_NextYearTeam from the dropdown menu. Set the value to the ID number of the team you want to populate (find the number by clicking on Teams, under Parameters, on the left of the main PowerScheduler page) and then click Modify Selected Records on the lower right. To retrieve a list of students from a certain team, use a search like this on the Students page: Sched_NextYearTeam=2781.