'Other' row in the workflow board

On the workflow board it would be helpful to have a row for all items that are not visible in the other rows.

Two example use cases.

1. Features board: I want to see all features in a product, but I am particularly interested in individual users.

2. Requirements board: I want to see all the requirements in an individual feature, but I don't want to have to guess at who is assigned the requirements. If somebody that is not on my board is assigned one of the requirements, it would appear in the "Other" row (currently is will disappear from my board.)