How to stop getting notifications from a group inbox?

I have been placed in a group convo with friends and i don't want any notifcations from it but when i leave they be annoying and re add me into it, i have turned alerts from it from my Iphone Facebook messenger app so that's good, but what about when i go on a computer?

Go to the group message which you received! Click actions of top right corner! Then click report as spam!
then you wil not get the messages and they can't add u again, or in my opinion… If you leave the conversation once they can't add u… It displays that the user already left the conversation once! Try leaving the conversation first!

Change the notifications settings on your account settings page - under "all notifications" - select "group" and edit the settings there.
Also in chat under group convo, select "leave this conversation".