Iam tryin to make multiple extensions ring when a customer dials 1 in the auto attendant. I see where u can only assign extensions not hunt group pilot numbers

You would want to create a calling group or hunt group, which ever one you prefer.
Then point a selector code to that group.
But I don't recommend using 1 as a selector code.
If your dial plan goes through, lets say 32, I would start with my first selector code being 4.