I don’t know if it’s something that would get added as a script to the Automation plugin, but if you are able to install custom plugins on your Discourse site, you could add it via a plugin.
I’ve been wanting to learn how to create custom automation scripts for a while now, so took this as the chance to do that. Please don’t use this as it is, but here’s an example of how to add an automation script for updating Activity Summary preferences when a user is either added or removed from a group: Create custom Automations - #6 by simon.
The reason for the warning is because I can imaging automation scripts going horribly wrong 
At the very least, the plugin needs some tests. I’ll try to get some feedback on the code and update it if needed.