Or, if they're in a forgiving mood, this will produce one e-mail address per line, regardless of delimited position, (assuming the founders were already on separate lines):

 | sed -E 's/^.*[^[:alnum:]\._\-]([[:alnum:]\._\-]+@[[:alnum:]][[:alnum:]\-]+\.[[:alnum:]][[:alnum:]\-\.]*)[^[:alnum:]\-\.].*$/\1/' 
 | grep -E '^[[:alnum:]\._\-]+@[[:alnum:]][[:alnum:]\-]+\.[[:alnum:]][[:alnum:]\-\.]*$'