I'm going to bump this, although just a suggestion.
Is there going to be any changes to restrict or specify source on the player end? It kind of gets difficult to create in my example with ARMER I want to create a Minnesota State Patrol playlist when different sources may have different length tags, simulcast, or other issues that cause a duplicate to appear within the playlist. Sometimes one source may be more consistent while one may be mangling calls it seems as well. It would still be nice to leave the option of a 'wildcard' within the source list by default but allow the option to specify the source node within the playlist editor.