XF 1.2 Avatar Border based on Rank

Hey All,
Currently my userMessageInfo is like this:

I would like to have it so that any staff (possibly just have it as the users that are set to 'Display as Staff') have a border around their avatar.
Like this:

I was thinking that this probably would have to do with the helpers for usergroups, but I have no idea how to implement it myself. Any help would be greatly appreciated!