We are sending one campaign to two different subscriber lists. The content of the email is the same, except that all the links in the email will have a different tracking code depending on which subscriber list the recipient belongs to. The urls look something like: someurl.com?trackingcode=<campaign_name><subscriber_list>
What we've done up to now is send them as two separate campaigns, one to each subscriber list, with a different hardcoded tracking code on each. The problem with this approach is that there are persons subscribed to both lists, and thus they receive duplicate emails (Campaign Monitor cannot weed out duplicates across two separate campaigns).
What would be a good way to achieve this without having to send two campaigns?
Sure, you could set this up using custom fields and personalization, this blog post has some good examples to work with.
If you send to both lists at once, it will automatically de-duplicate the list so those subscribers will only get one email. It will automatically select them from the list they were added to first, when they subscribed or you imported them.