What would you like to accomplish? Would you like one account to sync? OneNote will look across the various accounts to see if there are any notebooks that can be synced. You will have to sync per notebook to be really in sync. I have various accounts on various devices and OneNote finds them all. For me this is the perfect solution because that way I don't have to worry about the various devices being in sync. However there is a registtry key which you can edit to just sync the files you need and remove the other entries there. I wrote a blogpost about this here
http://wp.me/p57J76-8W. When you have created the registry file you can see all entries in that file. Remember tampering with the registry might make your system instable!!!