Well, thanks for the vote of confidence, but you're pretty well stuck on the PVM card. About the best you could do is:
Take away Ext. 10. Make it some other extension. You can still program from Ext. 11.
Connect a bell to Ext. 10, and place it where everyone can hear it, or use multiple ringers.
Put a "pickup-10" button on all the other sets.
You could loop Ext. 10 back to a CO port that you assign to the extensions but not in their auto line select, but as soon as someone answers an incoming call on that "line", it blocks it to another one. If you restrict the line as "No Access" in #302, I don't know if it will also cancel the ring. If it doesn't, give it a distinct ring, assign it with no access to the other extensions, and still give them a pickup-10 button.