I don't know about on other sites, but on this one have her use this link
https://www.myepilepsyteam.com/people

And then use assorted filters (so she can choose the gender and age of each person. After spending a little time in this section, she can form that group of friends here. There are locations on the left where she can put in the JEM to help specifically create a teen group as you described.

Let me know if she has any other questions in the process or adding these friends to her team.

NOTE: Tell her to make sure to look at the date when this person was last on to make sure she has friends who are still active.