The only way for you to do this at this time is to have your friend's PC be a part of your Mesh, not another Mesh user invited to your Mesh to share a folder or folders. That means that the Live Mesh client on his PC needs to login with your LiveID - which
I do not recommend.
What you desire is something that has been asked for before, though.
Live Mesh Beta: Suggestions - Go cast your vote!
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