I'm a service unit cookie manager, and our council does the juliettes of each SU as a pseudo troop. I am responsible for acting as "troop cookie manage" for my juliettes. The main difference is that when I turn in money for them, I turn in the entire cookie price, and then at the end of the sale council totes up their "troop" profit and writes them "juliette bucks" that they can use for camp, SU events or at the shop.
I have an older girl who acts as aid for my troops (she is an older sister.) I also have some older sisters who have registered to come along for specific events that you have to be registered to do. Rather than registering them as in the troop, I register them as juliettes, so that anyone who wants to sell cookies can get those juliette bucks for their own girl scout activities, or they can participate to whatever extent they want.