You can't. Running the Internal Users URL will run all auto actions with the Internal Users trigger. This will be improved once the following ticket is implemented.
forge.joomlapolis.com/issues/7976
Basically Internal Users and Internal General triggers would be going away in favor of custom user sets. Those custom user sets can then be selected in an auto action to run the auto action against the supplied user set. Those user sets will support filters so it can filter at a database query level improving performance significantly with this behavior. You'll then also be able to run auto actions individually against user sets, which would cover what you're trying to do.