Is it true and reliable to recruit those cast members online?

It depends. It's generally unreliable.

Is there a cast that really lacks group performances? That's for sure. The information on the recruitment website can't be wiped out at once. There are indeed some jobs, but instead of believing these, it is better to go directly to the film and television city.

General scams are intermediaries. After you go, pay a deposit or an agency fee, and then leave. So it's best not to believe it, in case you are cheated.