When sharing content you have the option to choose what you want to share with Facebook.
In order to do so, just click the Facebook or Twitter icon at the bottom of the post to turn this functionality on/off for that post. If you attempt this prior to syncing your account with Facebook or Twitter, you will be prompted to log into those applications and sync with Myspace . You will be unable to share via Facebook or Twitter until that process is complete.
Remember, at any time you can disconnect Facebook from Myspace through you Application page.