This is sort of out of place in Quests but I was hoping to get a little insight from some other quest builders.  At the moment NPCs will still sell to you if you are Dubious to them.  Is there a way to prevent an NPC from selling to someone that has dubious or lower faction.  Did I miss something obvious and it should be working, or is it not yet implemented.  
If its not implemented, any suggestions on trying to go about accomplishing this? 
