Give them time. You are still new to them, and you have to earn their trust. You can try to put a yummy treat that they have to lick off of you on your fingertips. Try plain yogurt, or fruit baby food. Or you can put a bit on a spoon, and gradually move it closer and closer to you. Here is a website that has some good info on socializing. Www.joinrats.com
Some rats need more time but make sure you stay near them all the time and open the cage and offer yummy treats. It helps if the rats are in the busy part of the house so they can hear and be part of the household.
I have a trio as well but i got them all separately. I’ve had one of them just over a month and she’s just coming around, but still quite skittish. Just don’t force anything. I put a desk chair up to the cage and open the door and sit in the chair on my phone. That way she can explore me in her own way and return to the cage when she is scared. After she gets brave enough to come out all the way a time or two, when she gets scared and runs to the cage, she ends up running right back out on my shoulders or chest again a second later! Just be patient! It’s worth it!