Babysitter Needed for my Children - Full-time / Part-time

I'm looking for a part-time nanny in the South End starting in September for my three kids (11, 11, 6). They are all in school full-time in Back Bay, and I'm looking for some help with school pick-up, shuttling to afterschool activities, dinner, baths, etc. Ideally this would be 20-25 hours Mon-Fri 3-6:30 (but open to changing the times if needed). Thanks!