Adding a group to have permission to join a chatroom

is it as simple as having the group be added as "group@jabberserver.com" inside “User Permissions” option?

if so, it doesnt seem to work…

There is no option to add groups into room permissions. There is a ticket for this feature in the tracker and there was even a patch in the works, but we haven’t heard from the author of the patch for a while OF-179