Can I somehow setup that the endpoint (=exit node) shuld be in USA ?

To: "or-talk@xxxxxxxx" <or-talk@xxxxxxxx>
Subject: Can I somehow setup that the endpoint (=exit node) shuld be in USA ?
From: "Ben Stover" <bxstover@xxxxxxxxxxx>
Date: Sat, 29 Dec 2007 19:46:14 +0100
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Can I somehow setup that the endpoint (=exit node) should be in USA ?

How do I specify this in Tor or Vidalia?

Ben