Replace posts from certain usergroups with text or image

[wrongful]

I want to put a conditional in my postbit where if a post is from a certain usergroup that post shows an admin picked image or text, basically just different html rather than the actual post. I am doing this for my banned usergroup. I know it's done with conditionals I just don't know how to make them.

[Brad]

<if condition="$post[usergroupid] = '6'">Banned Text<else />regular post text</if>

That is the basic condition, you will most likely need to change the number 6 to the correct usergroupid for the banned usergroup.