Basically, people should be able to find others on the same quest as them so they could help each other. This would help connect people in the same way that the dungeon team up does.
Possible user-friendly implementations/ideas of how to do this:
1. You could to click a button on whatever you quest you want to find others with, and you can message the people who have done so with the same quest. Maybe also have setting for looking back 1 or 2 quests in the arc you are in, should you not be able to find anyone on your current quest.
2. You could have it as a setting on/off for whatever quest you are actively on, and have a sort of group chat, and/or a quest group list (like in the friends or group list).