Will my older female cats hurt my 2 new female kittens? ?

I have an 8 mnth old Tabby/Serengeti female and 12 wk old Tabby/Persian female kitten. I've recently brought home 2 beautiful 6 wk old female Calico/Tabby kittens and introduced them like all the websites said and my 8 mnth old cat just stares and sneaks up and paws at the 6 wk kittens when there playing and sometimes when there asleep. While my 12 wk old kitten is alot more aggressive and will pounce and bite the front of the 6 wk kittens throat and kick really fast with her back legs and growls deeply I'm afraid she might hurt them what should I do... No stupid answers pls