parent's B2 visa application

My parent's visa application have been rejected twice in shanghai, the
reason is as a single child I have never been back to china for 8 years. I
am planning to come back to china soon-in march, during which time, they
will apply for visa again.

There is a new contract between america and china at the end of last year,
saying if chinese citizen join in a travel group, the chance of passing is
much higher. My question is,

1. should I ask my parents join in a travel group or still I invite them?
which has better chance?
2. because of rejection history, they are going to get new passports, will
this be a good idea?
3. If they apply for visa from travel group, should they honestly say, their
daughter is in america? will this affect? anybody already has experience of
asking parent issuing visa as part of travel group?

thanks for any suggestion! I have 2 kids, my work will be very busy and
challenging, I desperately need my parent's help.