GetReponse With Subscribers From Different Opt-Ins

I'm looking at switching email services and am evaluating GetReponse.com.

I have several ways people can opt-in to my list - say Ebook A, Ebook B, Teleseminar C.
I will send 2-3 autoresponders (and maybe a broadcast) to people whop opted in via (say) Ebook A. Then they can be transferred to the main list and will be getting "All subscribers" messages. Same with List B and Teleseminar C.

Obviously I do not want to be charged 5 times if someone signs up for 5 lists (or buys 5 products with autoresponders). So keeping them in separate campaigns doesn't make sense.

Moving people manually to a main list is a HUGE amount of work!

I looked into segments. I was told the only way to create a segment when they opt in is to have a custom field and then segment by the way they *answer* the custom question. That obviously makes no sense, since I need to segment on the fact that they signed up, not on the response to the question.

I can't believe I am the only person who uses this model. I know lots of people who have multiple sources of opting in. Is there a way to do this in getresponse or is there a better solution with another email service? Or would I just accept the costs of multiple campaigns as a cost of doing business, since getresponse rates are fairly low?