If you have been using ProSeries for 30 years, the CD/downloaded version of TurboTax is your best option (don't use the main Interview; the "Forms" mode mostly uses the exact same worksheets as ProSeries).

My opinion:

(a) Tell 5 of them you are retired and they will need to have their returns prepared in another way.  If you want, you can review the returns before they are filed.  Or ...

(b) Pick the most difficult 5 returns and do them on your computer.  Have a family buy another copy of TurboTax and install it on their computer, and invite the other 5 people (the simpler returns) to their house to prepare and e-file those 5 returns.