This message is probably coming too late to help you, but yes, there is a much faster way to delete whole family lines. Firstly, backup your database (including the date in the file name for handy reference). Then if you mess-up you can easily restor it to return to where you are now, with nothing lost.
Use File menu > Export and select the lines you wish to delete as if you were going to export them. Check for the >> symbol to make sure you aren't selecting anyone you want ot keep. Instead of exporting them, click the Delete button, and they are gone.