I have about 10,000 people that I'm going to be moving over to a new autoresponder sequence, but i'd like to test the first promotion that i send to them. Couldn't I take half of those names and put them in a group and then assign the other half to another group? I know it's not exactly the best solution, but I was thinking this might be a workaround for now since I only want to do one test to an existing group of people.