title: Regex match first email address that isn't a specified email address
body: <p>I have a string with one or more email addresses in it, I want to use a regex to find the first email address that isn't a specified email address.  For example if my string contains one or more email addresses of the general form someone@somedomain.com but also may contain one or more occurrences of a particular email address exactly equal to particularperson@anotherdomain.com, how I can find the first email address that matches the first form and that isn't the second form?  Or to put it another way, I want the first email address that isn't particularperson@anotherdomain.com.  All the email addresses could be in any order.</p>