"Please direct all future contact to me through Attorney John Smith."

*click*

Note that you did not indicate explicitly that you have retained this attorney, which makes it legal. If this attorney does receive a call or correspondence regarding you in this case, they will contact you. At that point you can either choose to hire them or indicate that you do not wish to retain their services. In the event that you do not wish to retain their services, they must forward the information to you. They won't be pleased you used them as your answering service but it is legal.

I suspect, however, that this will stop before it gets to that point. Usually 'attorney' stops silly matters.