Ken -
The main issue you are running into is that we have not officially
made the API support all of the Autoresponder functionality. In fact
until 10 days ago when a user asked, none of the campaignStats methods
even worked for Autoresponders, though we quickly opened that up since
it was a quick and easy change to allow that.
There are two approaches you can try that should work to varying
degrees - both require using the start/limit parameters and tracking
where you are in the paging, then picking back up from there the next
time you need to collect data. While the lists should consistently
return data in the same order, it is possible for that to change if a
list member is completely deleted, so you may want to giving yourself
a little padding. The 2 methods you can use to do this are
campaignOpenedAIM() and campaignEmailStatsAIMAll(). For the former, if
you need to detect multiple opens, it returns the number of times
opened. For the latter, you can sum the number of opens for the same
effect or look at the timestamps returned for opens.
An alternative is to skip the paging and simple pull all of the opens
for an Autoresponder and deal with new opens using the same data.
Honestly I'm not sure how segmenting the list (assuming you mean
creating multiple lists) would help in this situation.
If I've overlooked something or raised more questions for you, let me
know.
jesse