Rule Chain List - don't show rules already added to Rule Chain

When a rule is already on the rule chain, the rule shouldn’t show up in the results as I search for others to add. This seems like a logical thing that would be the case already, and because our rules have naming schemes it can take a lot of time ciphering through which rules have been added already when they keep showing up. 

As an example below, I would not want the Advocate Score option to show up because it’s already added to the rule chain.