Users User1 and User2 and User3 - registered Joomla users are included in the standard group Profile Types - Registered Users.
User2 created event - event 6
User2 created a discussion - discuss 6-1 (
http://onlytest.ru/events/13-event-6-2/apps/55-discussions/item/12)
User1 add a like on the discussion and the answer in the discussion. User2 has just appeared - Like Your Reply Discussion in Group.
User1 created a discussion - discuss 6-2 (
http://onlytest.ru/events/13-event-6-2/apps/55-discussions/item/14)
User3 add a like on the discussion and the answer in the discussion. User1 has only appeared - Like Your Reply Discussion in Group.
Try it on my website. You can create and test what you want.
login - user1,user2,user3
pass - user1,user2,user3