But only people outside the jurisdiction of the courts are obstructing American justice.
No. The people inside the jurisdiction of the courts informed their foreign counterparts not to give them access to documents under subpoena (directly or indirectly). That's obstruction of justice.
Did the subpoena prevent you from informing your foreign employer of what was happening?
If your foreign employer would respond by preventing you from complying then yes it does.
What if you don't 'know that for sure'.
Whether you committed obstruction or not is going to up for the criminal courts to decide. But lots of people are in prison who got cute with the law. If 12 Americans believe you did know for sure, or suspected that was the likely outcome...
What if your local lawyer 'was certainly unaware of that' (once made aware, he will be dirty and have to move on.)
A lawyer participating in a criminal conspiracy has an even lower burden of proof to be disbarred.