Temporarily tag subscribers for a specific action

While viewing the members of a list, it’s possible to tag members of the list, and then perform actions based on that tag. This is list-specific, and the available actions are very limited and list-oriented.

I want to be able to flexibly tag and untag subscribers without regard to their list(s) and then perform various actions on tagged or untagged subscribers.

For example, I have “country” and “primary genre” as two of my subscriber attributes. Let’s say I want to perform some arbitrary action affecting just science fiction readers in the US. I could select them if I could tag all “science fiction” subscribers and then untag all “non-US” subscribers. Once the action is completed, I would want to untag all subscribers so that I could use the tagging function for something else later.

I’d hoped to be able to use a “temporary tag” attribute for this purpose, but I can’t find a way (within the UI, not at the database level) to bulk modify an attribute for all subscribers, whether based on certain criteria (“set tag to 1 if genre = sci-fi”) or just in general (“set tag to 0 for all”).

I’m open to any ideas on how to achieve this. I have a workaround for what I’m trying to accomplish today, but it’s a high-maintenance, low-scope workaround and thus not suitable for long-term use.