I know this topic may have been brought up before, but I think I have another way to approach it.
Situation:
Take two Subsonic users, each has there own server and each has made a login account on his respective server for the other. These two users do not want to share music files with each other and have disabled music downloading for each others accounts on their servers.
Problem:
One user is unable to see both his friends music and his music in one unified list on his server and instead has to log in to his friend's server to see his friends music.
Solution:
Add the ability for a single subsonic server account to make a second connection to another account via url with user name and password and then add the music list of the second account to their account. You should be able to see and listen to both your music and your friends music in your one account.
Thoughts and comments and appreciated.