Today a relation can be only for one blueprint, but this FR suggests having a relation that is modeled to be one of multiple blueprints. For example - "Resource" blueprint can be connected to one of - service, cloud resource, or on-prem resource, so we create this special relation, and for each entity the relation can be one of the connected blueprints. For mirror properties, you will be able to mirror only the common properties (meta properties, and intersecting ones)