In Part 22
Figure A-3 – Modelling Example for PriorityMappingTableType and IetfBaseNetworkInterface
the NetworkInterface is configured on the WriterGroup transport settings

But in Part 14 we have currently the following definitions:

UDP multicast:
The Address parameter for WriterGroup datagram TransportSettings shall be null. If an Address is configured on a WriterGroup, the WriterGroup PubSubState shall be Error. The NetworkInterface field in the Address is required if more than one network interface is available.

UDP unicast:
The Address parameter for WriterGroup datagram TransportSettings shall be configured. If no Address is configured on a WriterGroup, the WriterGroup PubSubState shall be Error. The NetworkInterface field in the Address is not required and should be null or empty and shall be ignored.

In both cases, it is not possible to configure the network interface on the WriterGroup.

I think the intention for multicast was to NOT overwrite the address but we would be able to allow the setting of the interface. The NetworkAddressDataType has only the network interace field but the DataType is abstract. But we can state that the URL in the address shall be NULL or the complete address is NULL but it is allowed to overwrite the network interface.

For unicast we added the network interface clarification but we did not have the interface selection use case from Part 22 in mind.