How can i stop our green cheek conure from biting?

We just got an 8 month old, and it seems like he's attached himself to me. I greet him every morning, snuggle with him, and he seems to love it. The other family members try to get him to come to them, and he bites them, and really hard. How can I stop him from biting them?...I really don't want to return him.