I think that there should be a search field, like the one on iTunes, which allows one to search song names, album names, and artist names all at once and individually, but, also, all the other fields Jaikoz has should be searchable. That way, one can work with specific songs that may not have normally able to become close enough together on the list of songs to work with a specific list of songs together at once.
Search Field
This would be a custom filter, this is a good idea, a similar idea is already on the list.