When you send a broadcast using Aweber, do you have to send it to an entire list? If you have a list of 1,000 does it have to go out to all of them? If not, and you want to send a broadcast out to say, 100 people, how do you do that? Can you choose which 100 you send it to, and track it so you can send it to a different set of 100 people, for a total of ten times and reach your whole list of 1,000 over time? Thanks!