Hi Matt,
If you want to be able to see who has been picking up calls you should try and get a call logging/call account solution. There are several on the market available.
Few examples of manufacturers of these systems are:
Tri-Line (I admit I work for them)
Oak
Tiger
I am sure there are others as well. Best thing is to do a google and ask around to see what you want.
If you have any questions please let me know!
Best regards,
Andy