A mechanism for controlling configuration of dual connectivity for a UE that has a first connection with a first access node. The first access node could make a determination what type of UE the UE is, such as whether the UE is a relay-UE or rather an end-user UE for instance. Based on the determined type, the first access node could then control whether to apply blind addition or rather threshold-based addition in adding for the UE a second connection with a second access node. For instance, if the UE is an end-user UE rather than a relay-UE, then the first access node could apply blind addition rather than threshold-based addition, and if the UE is a relay-UE rather than an end-user UE, then the first access node could apply threshold-based addition rather than blind addition.