Currently Igloo does not offer that functionality on the platform. Notifications related to comments on content andare only sent by email. Users can disable these notifications entirely in their Subscriptions (located under their username in the User Bar), but there is no option to redirect these notifications.
If you would like to see this as a future feature on Igloo, please submit your idea to our Product Zone page here. Once you have registered, you will not only have the ability to submit your ideas, but you will also receive a notification any time the status of the idea gets updated by our Product Team. In addition, you will be able to view ideas that other Igloo users have submitted and up-vote submissions that you are also interested in seeing on the platform.
Please let me know if there is anything else I can assist you with.