Yes you can.

First follow these instructions to set up both a YouTube and a Facebook output in your system:

https://my.aximmetry.com/forum/postdetails/13-how-do-i-stream-on-youtube-facebook-or-twihttps://my.aximmetry.com/forum/postdetails/13-how-do-i-stream-on-youtube-facebook-or-twi

When Composer restarts you'll have two new outputs. Select them as output #2 and #3, and put the Sync on the first one  (but make sure that their frame rate is the same, in this case p30 !):

Start the Composer and go to Preferences:

Go to Channel Matrix and set it up so that both your YouTube and Facebook outputs are assingned to Channel 2:

This way the second output of your virtual set will be directed to both the YouTube and the Facebook output. You can click OK and start streaming as described in the post above.