You can use automation rules to subscribe or unsubscribe people to/from a list, based on them subscribing or unsubscribing to/from a different list.
Available Automation Rules
|subscribe-on-subscribe||Joe signs up to list A. He is automatically also subscribed to list B.|
|unsubscribe-on-subscribe||Joe subscribes to list A. He is automatically unsubscribed from list B.|
|unsubscribe-on-unsubscribe||Joe unsubscribes from list A. He is automatically unsubscribed from list B.|
To Create An Automation Rule
Go to the "List Options tab and click on "List Automation".
Go to the "Current List" dropdown menu in the upper left-hand corner of the page and choose the list that you want people will be added to (in the case of subscribe-on-subscribe) or removed from (in the case of unsubscribe-on-subscribe or unsubscribe-on-unsubscribe).
Click the dropdown menu in the "Action" column and choose the appropriate rule.
Click the dropdown menu in the "List" column and choose the list that should trigger the rule (when someone joins this target list, the rule you just selected will take place).
Click the "Save Automation Rule" button, and you're done!