Currently it's not possible to specifically turn off the "@all" mention for a room or a user.
I found an idea in the HipChat Forum suggesting this to be implemented. Please consider voting for it and following the topic directly in it: https://help.hipchat.com/forums/138883-suggestions-ideas/suggestions/4443200-ability-to-administrativly-disable-all-for-a-room.
If this notification is becoming a problem for now I'd suggest reinforcing the users to avoid using the "@all" mention and, instead, use the "@here" mention, which would call the attention only of online users, without sending them an email. You can find further information on how mentions work at https://help.hipchat.com/knowledgebase/articles/64429-how-do-mentions-work.
Consider using HC Alias addon, to give room visitors alternative for @all. E.g. we have rooms per team, but other visitors like members of other teams can be in the room of another team, and they would not like to be notified through @all but still you want to allow visitors to address team members only. So using HC Alias addon in every room we defined @team alias with only team members, so visitors can address team only.
...from the beginning. We have built up a lot of content in HipChat, with it being a core tool in our distributed company model. While it is true that we didn’t need to move to Slack immediately, we felt it...
Connect with like-minded Atlassian users at free events near you!Find a group
Connect with like-minded Atlassian users at free events near you!
Unfortunately there are no AUG chapters near you at the moment.Start an AUG
You're one step closer to meeting fellow Atlassian users at your local meet up. Learn more about AUGs