Autoresponder integration

my need: to sync my mailing/autoresponder service ( aweber, getresponse, mailchimp) to membership2.

I have different memberships, each requiring their own mailing sequence. I have upgrade paths, requiring my users to be switched from one list to another.

I know about the mailchimp integration, but it's pretty useless as it is, for a simple reason: it registers any and all membership users to the same unique list. But I have recurring memberships, of different lengths, one-time purchases, etc.... Definitely not a one-size-fits-all in terms of mailing sequence.....

I'm about to fire up my system, I'm kind of hitting a wall here, I'm open to suggestions for workarounds or solutions. If I don't find a way I'll have to manually add, remove, switch my users every time something changes in their memberships.... Headaches in the long run, but doable.....

Etienne Bovo