Add-on Per User Group avatarHolder

So we are currently transferring our forum from vBulletin to xenForo however I have just come across an issue that I completely over looked and I guess took for granted within vBulletin.

Our old vBulletin forum allows you to set a particular picture for everyone in a certain group (kind of how titles and promotions work, but with avatar pictures)

Now xenForo doesnt do this I have asked the community guys and they say it is only really possible with an addon.

Hope someone can help :)