Why is Distribution Mode = Sequential not working for Hunt Groups?

Here is what we want: When someone calls and presses 1 for the Support group - the call should do the following: start at ext 331 if busy/no pickup after 2 rings, try ext 316 if busy /no pickup after 2 rings, try ext 319 if busy /no pickup after 2 rings, go back to ext 331 & leave a voice mail. My phone guy swears we should be in Rotary Mode. But that doesn't really make sense. I think it should be Sequential Mode. But it's all a moot point, because when I test the system in either of those Modes, it does the Broadcast thing (rings all 3 phones at once, then after a while the person gets a message that says "we're sorry the person you are trying to reach is not available - goodbye".) Right now we have Mode=Rotary, hunt delay=2, Busy=overflow, Queue time=30. Is there some other setting that I am missing here to get the system to do what we want?