Hey there! It would be great to have an efficient way to create exclusion lists. The tag system is a cumbersome process to go through when the goal is to simply send an email to List A, but exclude anyone who is also on List B. If a checkbox-to-exclude feature became a reality, you'd have a lot of happy customers! (I did search the "Constant Contact Community" when trying to find out how to exclude a list BTW.)
I didn't necessarily want to post this particular message to the entire "community" but I couldn't find a way to just email my exclusion list request to your developers.
We are considering this as Implemented with the addition of “AND” and “IS NOT” logic within the segments feature. You can now create a segment for those who are a member of List A, and not a member of List B. After this implementation sometime around mid-2021 we’ve seen requests on this particular feature drop off across all of our feedback channels.
There was a large variety of use cases for this particular request, so this was the solution that had the widest range to address most of them. If you require additional filtering needs, you may be interested in adding your voice to one of these existing open ideas: