External Call Queues

Hello everyone, an Asterisk newbie here!

Here’s what I would like to accomplish: Someone calls a 1-800 number that goes to my Asterisk server, and a receptionist pick up the line. The call needs to be transferred outside the company to a bank of specific people (that would be in a queue) and it would ring the people in the queue “round robin” style until someone picks up the line. I installed AsteriskNOW, and in the call queue menu I can see the option for round robin, and adding people to the queue seems easy enough, but I can’t add people to the queue that are external to the company. Is there any way to do this?