My friends and I have Ubuntu One accounts that we use personally and we also have an account that we all share the login details for which we use for sharing music.
What would be amazing is if we could just sync our Music folder under our Home folder to the account we share and have our personal accounts sync to the Ubuntu One folder. That way we wouldn't need to log in to the Ubuntu One website and we could share music through the desktop client.
Is there any way to do this?
You cannot use multiple accounts with a single local user on the system. You will need a separate local on your system, logged into another Ubuntu One account with the client, to have a client which syncs with a different account than your normal user is.
However, instead, you (or any one of your friends) could simply share a single folder to everyone else, and allow them write access as well, if you wish to synchronize a single common folder between everyone. Whoever owns the folder will have any space usage in that folder, deducted from their account's quota. You could also share a folder to each other as read only, so the data usage is distributed, and you can read all the files you want to share amongst your group.