- MAC address filtering on every router that I have seen either allows a particular devices MAC address or does not allow it. I have never seen a router with programmed MAC address filtering.
- Only network nodes such as computers, broadband modems, Wi-Fi compatible mobile devices and such like have MAC addresses. People do not have MAC addresses. Teenagers are people. Therefore, teenagers do not have MAC addresses.
You need to better define the problem that you are trying to solve. The ask for help developing a solution that will actually work.