better way to link netherportal linking

A block that can be placed at the corner of netherportals that helps linking portals that are close to eachother. That way you can have multiple portals link to one in the nether or the other way around and you can have portals of farms or a hub close together without having problems linking them. My idea is to set filters for the portals in a special block in the corner or in a form of a book you throw in the portal the same way as in the infinet dimensions snapshot.