I know this is an old post but it never hurts to revive an issue that still needs a solution. This is one of those problems that we unfortunately need to find a workaround for until Autodesk can give us a better solution.
I've been looking into Dynamo and there MAY be a way to get this to work but for now here was my workaround.
To limit the items that populate the list I created my embedded components using a family type that we don't use in our models. For example, I work in Architecture and don't use the sprinklers or data components. I created several door panels using the sprinkler template. I embedded those into my door family and now when the user goes to pick which panel they want they only see those items.
Seems very counter-intuitive but it has worked well for us.